I’ve found most to either be a) you are flagged as malicious by their system and routed thru their process to prove you are human; some you can end up locked into, b) they gate content or services. Mostly the latter but the former is becoming prominent with all the fuss about AI. I imagine they are training protection models on us.
Mostly it’s just convenience you lose, having to always add a protective layer (like temp emails, etc.) while everyone is good to go. Managing all that can be a chore too. Or seem like one.