My main use currently is a modded Minecraft server. But I want a VPS over one of those Minecraft host specifically because I plan on messing around with docker containers later and hosting my own Lemmy instance. Currently I have an openVZ server from TNA hosting because it was like $50 a year. But it's not powerful enough for the Minecraft modpack.
Tried a few weeks ago. They wanted my card to check that I am not a bot (I am fine with that), the 0usd transaction succeeded but then I got an error message.
God knows what they'd have flagged. I was trying to sign up to sendgrid's free tier to test their SMTP server and got instabanned before I even got the verification email.
Just don't try to run huge amounts of bandwidth or try to pirate content on it and you'll be fine.
It does need a credit card on file, but it cannot charge it unless you explicity disable free tier.