The fact 3PID invites create guests rather than registered users is very confusing

[ara4n]

@BenfLewis0 points out that inviting someone by email can backfire as they will be a guest when following the invite, which makes their account worryingly ephemeral.

Options to fix are:

• Put them into a registration page anyway to give them the option of creating a real account (or signing in with an existing account if they choose)
• Improve the process of upgrading guests to registered users (i.e. probably ditching the numeric user ID, which is basically the same as Avoid guests from being stuck with numeric IDs #2947)

[t3chguy]

This is no longer the case because now you're forced to register