I did the same, but i still use Cryptomator for stuff like sensitive documents and the sorts, much like i would have used an encrypted image before using cryptomator.
iCloud works great, and even if you trust Apple (which i do to some extent), your data is still only safe as long as nobody gains access to your devices. Once somebody has access to your devices, files are no longer encrypted.
The choice of Cryptomator was a convenience choice. I could have just as easliy encrypted files using GPG, LUKS, encrypted disk images or similar, but i would not have been able to access those directly from my phone/tablet in their cloud location, which is something i can do with Cryptomator.
For reference, i have about 4TB data in the cloud (~3.5TB photo library), and a 2GB Cryptomator vault, so it's not exactly the main driver of the operation :)
