You should properly protect your email, because when someone hacks into our email, then they might have access to some sensitive informations which they are not suppose to have access to, so gmail is suppose to be properly protected. If anyone investing in bitcoin are still leaving their seed phrase on gmail or drives, then they are not really serious.
Its always been warned that we are not suppose to leave our seed phrase in anywhere there is internet connection, but some people still decide to do whatsoever every they want. Your Gmail can be compromised at any moment, so if sensitive informations are there, then hackers will be able to take it easily. Its easy to store your seed phrase online, but we should know its not safe, so since we know its not proper, then we should avoid it.
Convenience is the main issue here bro, that's how everyone loses their coins and funds, they go for convenience. They don't like to write their seed phrase, they like to take screenshots and then lose them somewhere in the gallery, while finding them is easier if they write them in notes, but then again storing them on devices with internet has never been a smart move.
But still they will go for convenience and they will find a way to store them safely somewhere online, even on cloud servers. They can encrypt them in a way that only they can decrypt. But we should not encrypt the whole seed phrase in one go. Instead, do that in parts and save them in different places, although I have a few plans that I can't share here haha to secure your seed phrase manually, but it's like hiding them in words.