I've given some thought as to how to make Bankify not require an open browser tab. Here are my thoughts so far.

There are a few services that let you spin up a cloud computer (a "virtual private service" or VPS) and let you pay monthly via lightning. I could give a button to the user where, if the click it, it shows them a lightning invoice, and if they pay it, it automatically spins up a VPS for them, installs the requisite software, and then hosts their wallet there, with a monthly reminder when it's time to pay their bill.

But there are a few parts of that job that are tricky: these services usually email you the log in credentials for your virtual computer, and you have to get those credentials, then log in in order to install the software needed by the user. So in order to automate this I would have to set up some service that can receive emails, parse them, automatically use parts of the parsed email to log in to a VPS and install some software, then somehow deny myself future access by deleting the password or something like that.

And I would also have to show the user some sort of loading animation for, like, several minutes or so, and hope they don't just get mad about the delay and "x out" partway through. This would also break if the VPS host ever changes their email format, meaning I would have to maintain and update the software occasionally, and users would have to be made aware that they are trusting the VPS host to (1) stick around (2) not read their private keys and steal their money.

This is all very imperfect so I seek a better solution. When there are free custdial services available, how do you convince users to pay for the-same-thing-but-worse?