I suggest that you change the label "email" to "username"
He could use that option, but than he would need to add information that
@ symbol is required for the username.
Something similar is used in some log in services when they ask you to make password more complicated with addition of special characters #$%& or brackets, in addition to letters and numbers.
In addition I would add information to create more complex ''email salt'' because if you use something like I did x@x it can be cracked much easier, intheory.
I would also add a button "generate random username".
I wouldn't do that.
After doing some research I found out that random is not always random, especially if generated online on websites.
I looked at USDT rich list and there are still some usdt in omni (bitcoin blockchain)
Isn't it better yo use it?
I don't know if there are testnet coins available for that, and I think that RobinLinus is not using USDT directly.