The answer is in the forum XLR output on Fender Rumble 40 - #5 by howard 
It doesn’t mean it is not usable, in most cases it should work ok… just be aware it is not the perfect solution for all cases
And for the next question, that’s personal. For my taste, a graphic EQ pedal with DI out would be almost enough for everything (at least since https://www.youtube.com/watch?v=-77UU4ZzG4c )… what would you like or need?