You see ProConnect related to QBOA, because QBOA = the A is for Accountant Portal.

Being a QBOA user means you would be expected to be a professional that is using the portal to manage client files or support those clients that use QBO, and then the connectivity allows you to transfer QBO data to become the basis of income tax filing for that same entity. It's cross-marketing and integrated for reasons of trying to keep Professionals "in the family" by Intuit.

Of course, a QBOA user can also be a person who has many irons in the fire and manages many of their own entities under separate QBO accounts.

You can use any tax product on the market to do taxes, and even the free file functions, of course. Only you can determine if you are stepping into a Professional capacity or staying as DIY. Then, you get the tool(s) you need for what you intend to do. For instance, your personal life might be complex enough that TT does not meet your needs, personally.

The issue of efiling or not is its own consideration. Many States are requiring it and in the "time of covid" it seems better than paper filing for the Feds, of course.

ProConnect is like any other app, and there will be issues as you use it. That is different than tax regulation issues. If you rely on the TT "experts" to support your own tax questions, I think you will find a very different experience if you switch to using ProConnect and then start asking for personal tax guidance here.