Yeah, that's a common thing when we were young onto this market and we thought that doing it was fine.
Not until we've come to realize that it's very unsafe and not recommended to be done.
Thanks to the early adopters and those that have told us that it is a bad thing and a terrible idea to do.
I don't do this anymore or if I do, it's for some thrown away wallets that will never get any deposit from my pocket.
Yes, luckily my bitcoins were not stolen until I realized that keeping the seed phrase in plain text without any encryption was an insecure act that could result in losses from malware or malicious third parties. Then I ventured into encryption tools that aren't very secure. After learning a little about Linux, my security standards and criteria increased.
However, if the funds are stored in a hidden wallet accessible via a strong and random BIP39 passphrase, nothing will happen to your funds. However, I still don't recommend leaving the seed phrase hosted online in any way, especially without any type of encryption.
Two risks here
A close source wallet.
A command or suggestion to require users backing up wallets on Google Drive. It's less likely the case with any wallet but if any wallet asks users doing this step, it's very dangerous and you should migrate your coins to a new wallet brand as soon as possible.
A close source wallet is not recommended for using because it's irreproducible and it's hard for users and community to check and test whether there are backdoors in the wallet code.
Trust wallet is close source, if you wonder whether it is not close source, this wallet review confirms it for you.
https://walletscrutiny.com/?platform=allPlatforms&page=0&query-string=TrustAlso, be wary of any pop-up windows from applications that suddenly appear asking you to back up your private keys (e.g, make a backup in 12 hours or lose everything). No wallet will ever ask you to re-enter your backup words.