> currently possible to use it without giving them a phone number
I haven't created a discord account in a long time, so I'm not sure what the flow is, but my recollection is that phone numbers are required iff the specific server (community) turns that on as a security feature
Try it out, I don't think there's any way now. And it's really easy to get completely locked out of your account if you connect from a low-reputation/datacenter IP, like through VPNs or Tor.
I haven't created a discord account in a long time, so I'm not sure what the flow is, but my recollection is that phone numbers are required iff the specific server (community) turns that on as a security feature