they are not very good for hosting user generated content, they suspend very fast for any sort of Abuse complaint. User generated content, will result in some Abuse complaints.
I host a lot of production there, but always some layers underneath - like a high CPU or backing storage layer or database, worker nodes that pick up tasks. Never the front user facing.
Do not let any user generated content be accessible from any hetzner IP or you are one email away from shutdown pretty much. Don't forget germany's laws on speech too; they are nothing remotely similar to US. I would host, for example, a corporate site just fine, but last thing ever would be a forum or image hosting site or w/e