Cold wallets, or hardware wallets, give more security than online wallets; they have additional security that doesn't just make it easy to hack, so if you can set up a cold wallet, you don't really need to have multiple online wallets.
I do really prefer hardware wallets, but it is expensive and not that affordable. That is why others are sticking to online wallets, and to prevent getting hacked, they will be creating multiple wallets that they spread across their bitcoin. If you already hold a huge chunk of bitcoin, it is better to use hardware wallets to be more safe, and you can carry it everywhere you want or store it in a safe.