Well offline wallets are secure for a long time savings. for example if you want to save your bitcoins for a couple of years, then never use online wallets. But online wallets are better if you want to receive and send payments as a routine.
You do have a point, but there are also online wallets(not totally online) like Electrum which is good to store our bitcoin unlike any other wallet here online. Hardware wallets like Trezor is an example on where you could also store your bitcoin safely in the long run, the only difference between offline and online wallets is their security.
