This can be useful, not to check whether everything is okay but just in case your device gets into the wrong hands. If you have your funds in a wallet or maybe an exchange platform that you have on your mobile phone, and if your accounts are all logged in. Some apps won't even ask you for verification every time you open it unless you have enabled it, so anyone who unlocks your mobile phone can easily access your account, and if you have your 2FA method saved in the same phone such as Google Authenticator, then your funds are gone.

So even if it's a bit of a hassle to log out and log in every time you want to use those apps, it can prevent your funds from getting lost in case your device is stolen or lost, etc. However, it is better if we lock such apps in ways that wouldn't allow anyone other than ourselves to be able to open them instead of having to log in every single time.

Many people don't even have 2FA enabled on their accounts, which is a very big mistake.