So one thing I don't really understand is the lack of elisions in esperanto speech casually and why they are mostly discouraged. At least from my perspective it makes the language much more natural sounding and objectively easier to pronounce and faster. Instead of "la amiko" it becomes "l' amik'" which is just, I'm sorry but that is like objectively better, right?
I also see this on and off, and it's with the lack of using adjectival verbs as copula for an adjective.
I know that this guy was probably a beginner and all, using "ĝi" as an abstract concept, but even so in response to "why learn esperanto?" a fellow esperantist said "ĉar ĝi estas amuza" where I would've just said "ĉar amuzas". I feel like esti is cool but it can be kind of a mouthful for everytime and if we have this more efficient usage for adjectives then why do we mainly only reserve that for poetry?

This boils down to the word building in Esperanto. More precisely the question is, whether you can create verbs from all roots. There are people who claim that you always can. Let me analyse this.

From nouns you generally cannot. What would domi mean? Of course there are such as marteli, but that does not mean esti martelo. Note that there are a lot of preposition + noun + -igi/iĝi combinations, e.g. surtabligi, enlitiĝi. But from plain nouns, no, you generally cannot create verbs.

Creating verbs from verbs means changing the ending from -i to -igi or -iĝi, which is not relevant to this question.

When it comes to pronouns, numbers, prepostions, table words and simple adverbs, the situation is the same as with nouns: generally cannot. Some notable exemptions are anstataŭi, ĉirkaŭi, enigi (not an exhaustive list).

So in essence we are talking about turning adjectives to verbs. Turning them to -igi or -iĝi verbs is easy, beligi, to make beautiful; beliĝi, to become beautiful and so on. How about to i-verbs? There is a poetic expression by Claude Piron, a renowned linguistic and esperantist:
 

• Kiel bluas la lago!

Here blui does not actually mean "to be blue", but rather "to shine in blue".

Take another example. The adjective laca means tired. Again lacigi means to make one tired, as in la longa legado lacigas, and laciĝi to become tired, ne laciĝos mano, ne fariĝos pano. Zamenhof takes up several times that a word or an expression should be understood as "what it logically means"(*). This raises a problem: do all people understand it the same way? Are you sure that laci would for all, or at least for enough many, mean "to be tired", since there is no definition for it in a dictionary?

You can think that adjectives fall into two categories when it comes to verbifying them.

1. those with the meaning of "to be XX", e.g. beli = esti bela
2. others

Because we cannot change the verbs in the second category, let us minimise the number of verbs in the first category, so that we do not need to remember by heart to which category a verbified adjective belongs. In other words it always more preferable to say estas bela, amuza…

To complete there is a short list collected by the esperantist Lee Miller and that list contains the established verbified adjectives.
 

• Mi feliĉas° : mi sentas min feliĉa
  
• Mi malsatas : mi sentas min malsata
  
• Mi malsanas : mi estas/sentas min malsana
  
• Vi kuraĝas rakonti : vi havas kuraĝon rakonti/vi estas kuraĝa kiam vi rakontas
  
• Mi fieras : mi sentas min fiera
  
• Tio sufiĉas : tio estas sufiĉa
  
• Ŝi pravas : ŝi estas prava
  
• Ĝi utilas : ĝi estas utila
  
• Ĉiuj egalas : ĉiuj havas la saman valoron/ĉiuj estas egalvaloraj
  
• Mi kontentas : mi estas kontenta
  
• Ŝi tre lertas° : ŝi estas tre lerta
  
• Mi lacas° : mi estas laca
  
• Ne gravas : ne estas grave
  
• Mi pretas° : mi estas preta
  
• Li kapablas : li estas kapabla
  
• Mi certas : mi estas certa
  
• Tiom da aferoj necesas : tiom da aferoj estas necesaj

° = not in PIV

*: If I am not recalling wrongly, one of these "use logic" statements is precisely this, one should not assume the "to be XX" interpretation of verbified adjectives.

This writing is partially based on the article "Esperanto Adjectives – Love ’em, don’t leave ’em" by Tomaso/Salivanto Alexander.

so in response to "why learn esperanto?" a fellow esperantist said "ĉar ĝi estas amuza" where I would've just said "ĉar amuzas"

He should have replied 'ĉar estas amuze' (understood amuze lerni ĝin)- unless he thought that the language itself was amuzing. But Esperanto isn't a joke.

Was the Esperantisto a native speaker of English? He might have been translating in his head because it's fun which in Esperanto should not be translated with ĝi.

Are you sure that laci would for all, or at least for enough many, mean "to be tired", since there is no definition for it in a dictionary?

How strange. Is it not in PIV?

The usage, anyway. can be researched in la Tekstaro. Where the meaning seems to be be tired or be weary of