Adding the digital download to the cart was fine, but the first step of checkout is logging in again because you're making a purchase.
And then needing to log in again and again, ad infinitum, never getting past that crucial first step. The login options are by password or by verification code, but the result is the same. It shows an error message when bad data is entered, but another login prompt when good data is entered.
Like it or not, Microsoft has a productivity suite monopoly, and your program can't break that monopoly by being scarier and more confusing for ordinary users when saving files.
Opera didn't break Microsoft's browser monopoly, but Firefox sure did (before Google captured it again for itself), and it was by being genuinely easier and better for ordinary computer users, not just for tech-minded nerds like me.
The daffy boxes of scrap metal named Copilot and Store Assistant were cheerfully eager, utterly useless, and completely unhelpful. But after an hour of boxing both it and Microsoft's old-store not Store checkout (because of course Microsoft has two radically different things with the same name), it connected us to a human robot powered by natural intelligence.