It’s the same reason why many people on the Bitwarden subreddit/forum recommend most people just to use Bitwarden’s servers rather than their own using Vaultwarden. Yes it’s hosted on a server that you don’t control and is definitely a much bigger target than your own server, but they have protections in place, a bigger team and they get audited, all of which are things that someone who did their own stuff at home wouldn’t have.
It is definitely much easier either using a cloud service that uses zero-knowledge encryption or encrypting files yourself before putting them on iCloud (or enable Advanced Data Protection), Google Drive or Dropbox.
Alternatively you just store everything locally, which is what humans have done for millennia (obviously as the World Wide Web was only invented in 1989 and made public in 1991). And it was something most people had to do in the early days of the internet as not everyone could use cloud storage. Google Drive, iCloud Drive and Dropbox brought that to the masses and made it very easy.