Do you think it is necessary while in fact anyone who use poorbot service do not even need to create an account.
What you need to do is just to fill the form with the required information especially Stake's username, the currencies (from and to) and the amount.
I think it is simpler and easier than using an internal account in the poorbot official site but of course they may consider your suggestion.
Almost a year now and seems that all poorbot users are comfortable enough with the provided service, poorbot would have upgraded it as your suggestion if most of the users suggested it.