Before, KYC was not actually a requirement on some exchanges. I have first experienced filling up for KYC verification on the times of bounty campaigns where bounty managers as well as the team developers of the project do wanted to ensure that the people they will be paying with is a real person having real identity. At first, that looks strange knowing that we are working anonymously using usernames to work in the forum then this KYC get through initializing a transparency when it comes to identity which the exchanges do adapt in order to secure its customers having a safe place to work with.
Now that because the government of a certain country wanted to ensure its people's welfare not to get into a scam exchange, KYC verification process is now being a requirement to be able to secure that people are really true and for security purposes. If it is not intended, I will not do the KYC process but since it is a requirement nowadays, then there is no choice but just to follow for why worry if you are having a clear intention on doing transactions.
Back in the past where KYC isnt really that too mandated yet crypto isnt really making some noise back then and when the market had become saturated and get involved with
lots of scams and frauds then government had already recognized its existence not only to this matter but also in taxation purpose as well and even on money laundering issue.
Nowadays there are platforms that do offer tx on maximum of 2btc per day which is sufficient but for people who do goes above that limit then there
would be no other options but to abide on whats being asked out.