Increment IDs or base64/hash for URLs?

I've built an app where users have "rooms". Each room needs an identifier.

I've decided against using "slugs" like example.com/room/my-room-name because I want room names need to be non-unique, permanent, multi-language. I'm sure there's solutions for all this, but that's not in the scope of this particular question.

I am currently using a numeric incrementing ID (It will start at a high number on launch). I more often see base64/hash type identifiers (Example: AwqLWGibwDY) in URLs (Examples: youtube, google docs).

Is this done for UX reasons, or for technological reasons. Is there a UX reason to use a hash over a numeric id?