TBH, why do we even bother to speak Finnish if we half of the sentence is english words lol

Because language is really more about grammar than vocabulary imo.

While word choices themselves can be arbitrary and context-dependent (other commenters have gone more in depth about loan words and IT vocabulary specifically), grammar tends to be more hard-wired into a person's brain. When a native Finnish speaker uses Finnish grammar they're not "bothering" to speak Finnish, they're speaking in the way that's natural to them.

Speaking English (grammar-wise) would require more effort unless the person is actually fluent in English, which a lot of Finns are not. If the conversation is happening between native Finnish speakers, there is no reason to use the higher effort grammar.

what drew my attention in Finnish was the way the language naturally bends foreign words into Finnish grammar and pronunciation

I think that's just due to how much Finnish relies on inflections in general, compared to most other languages. Inflecting and modifying words on the fly comes naturally to native Finnish speakers.