Not anymore unfortunately, at least not reliably. I picked it because of this ease of use, but I was forced to enter and verify an e-mail before it let me use it. And they reject mailinator.
That's a per-server controllable setting. The admins can set it such that only users with a verified email (and phone number if they desire) are able to send messages.
I used an unclaimed account for almost four years, only issue of course I had was dealing with guilds limited account based on verification. There was really no other problems
Unfortunate side effect of their success. Most bigger servers I'm on require having a verified account otherwise all you can see is a single message asking you to verify.