My 2 cents,
I Initially didn’t like the price of the Android software although I do donate to each of the open source programs that I use regularly such as Thunderbird and its companion program on Android called K-9. The difference is with those software programs you choose how much you want to donate. I also understand the need for the developers to pay their rent and food costs.
There are unsecure cloud providers like Google and Microsoft and there are others that encrypt the data on the server only they typically cost more money per month to use and when I compared the ongoing cost of paying for a cloud provider that had encrypted end to end storage I discovered that Cryptmator is ultimately less expensive over time.
Some cloud providers offer an encrypted area option for an additional fee that is usually also a lot more expensive than paying for Cryptomator.
The only big advantage that I can see paying for an end to end encrypted cloud provider is you can typically share a hyperlink to a file with somebody via email and you can’t do that with files that are encrypted with Crypomator. I solved that with three gigabytes of free space at Nordlocker. Anybody can have three gigabytes free there. That’s where I put files that I need to email to somebody and don’t want to attach the file to the email itself.
Before I calculated my investment over time I initially was a bit bummed out by the price of the Android software but ultimately it is a-OK.
I use the software on Android, Windows, and Linux and I recommended this product to a friend of mine who uses Mac OS and he is very happy also.