This idea is somewhat prevalent among native Chilean speakers, but I respectfully disagree. Even under formal settings, many of the features of colloquial Chilean variants are present, and often an additional effort to neutralize the accent needs to be made to sound “formal enough” to other Spanish speakers.
One thing is that pretty much the only place you'll see formal chilean is in like, the news, or official government communication. We're not very formal people, so even in workplaces or school we wouldn't use 100% formal register.
Sure, that is largely true. But, to state that the formal register of Chilean Spanish is “probably one of the most understandable ones, accent-wise” of all available Spanish registers is, in my humble opinion, quite a stretch.
Goddamn, is that what professional news outlets sound like? It sounds like a YouTuber trying as hard as possible to sound cool or edgy. Dude, leave the coke for after the broadcast.
Where the announcer is actually overpronouncing while still keeping (expectedly) some elision. In your example, Boric’s formal register is closer to what one would usually listen.
> chileans are ok with people saying we don't speak well
I never claimed that, I am merely addressing your “one of the most understandable” statement.
Only informally. Formal Chilean Spanish is probably one of the most understandable ones, accent-wise. (There's still some vocabulary differences)