The main benefit is that you won’t lose access to any content as it’s tied to your account.
But yes, due to arcane MS Store licensing rules most devs take longer to update it there. That’s a Microsoft issue.
Same goes for cost. Microsoft takes a cut of all sales, so of course they will charge more for the extra work required to get it on the marketplace (and maintain it there), especially when MS is taking a cut.
The marketplace will never be as robust as the outside add-on community. It just isn’t possible with current restrictions and content licensing rules.
Cheers