restrict people to 1 account
Users should be restricted to one Username.
If you require 2 accounts your already suspect.
Saying you need a personal and a professional account is countermount to the reason there is millions of accounts. however, If you need a way for someone to have a professional and personal username allow for just that TwitchPro and TwitchViewer accounts.
Alot of social media sites use a one account or rather 1 username rule.
There is no good reason for needing a second account registered to the same email address. This stops users from being banned and creating a new username to go harrass the person that just banned them.
TLDR: Stop the madness and quit fluffing numbers by allowing people to have 25 usernames.