Verification should always have been "This is who they say they are", not an endorsement.
The "algorithm" boosting tweets from verified accounts also showed it was an endorsement rather than verification.
When people lost verification for being distasteful, it reinforced the blue checkmark as being an endorsement.
The takeover sold-out the "value" build up from blue checkmarks by just straight up selling them. It explicitly made the platform "Pay for reach".
Why? Accounts can be sold/hacked, and there is a lot of that on social media. A verified account may even be a higher value target for some of the reasons you're bringing up, like algorithm boosts, verifications being considered an endorsement. In either case, unverification not only makes sense, but should be expected.
Such things could be ripe for abuse. Although to be fair a social media platform might be able to push some of the blame onto the corporate registries.
In short: originally the purpose was nothing more "this account belongs to the person they claim to be and we've directly verified this with them". Unfortunately, people habitually misinterpreted the checkmark as not just being verification but also a tacit endorsement of the account by Twitter the company. Which isn't great when you get a high profile controversial event and it's lead organizer has a verified Twitter account.
After that, they appended an "in good standing" qualifier, and it quickly devolved into a "you know a person who knows a person who knows a person" situation since they also announced a public pause of the program. (Notably, the ID check, while it existed, was pretty much abandoned. Twitter at some point began demanding ID scans to report things to their support, but that obviously never actually translated to a blue check.)
Musk's version of it is hilariously simplistic, but also robs it of any and all value: just pay money for it and you'll get it. It works in the sense that it confirms the poster has a bank account (although this probably doesn't confirm much in and of itself), but any and all value of said verification is minimal because any old hack/scammer can do that.
Verification is a difficult system to get right and people have all sorts of pre-baked in ideas on how it should work versus how it actually works and the use of a checkmark played a part into how Twitters version was perceived over the years. (As well as Twitters own unreliability in being consistent about what it means.)
[0]: https://blog.giovanh.com/blog/2022/11/01/the-failure-of-acco...
Oh you could also pay Twitter employees $20K under the table to be verified too.
Before that it was: "Someone will give you the checkmark if they like what you say enough and/or if you are deemed 'popular enough' according to an obscure committee; likely a combination of both. But there is a certain threshold above which it does not matter what you way, and you will always be verified". You could loose your checkmark on the whim of some dude who got his latte order wrong in the morning. No one was ever given the rulebook. In fact there was no rulebook. Checkmark just meant "I went to a bar with a Twitter employee and we agreed on a lot of things".
The same thing will happen to Bluesky. The system is akin to how CA and SSL does work with a critical difference. To get an SSL certificate, there is a clear step-by-step guide on how to get it. And after it has been granted it isn't revoked regardless of wether DigiCert agrees with the content of your website.
If I want to hear what a journalist has to say, I would go to their official website like NYT or Tagesspeigel and read it there. Should we be interested in what Kim Sang yun or Sebastian Mustermann has said few minutes ago?
The problem of spam and impersonation goes way beyond Blue Checks.
You are borderline arguing that information is bad (because that's all a verification is).
Are they the sole arbitrator if they simply use a DNS record?
That's the same tech used to verify their official website.
