I use online wallets, offline ones seem too much hassle for me, moreover I only have a very small amount of BTC that I don't have to be afraid of losing.
I also use online wallets because the process is very easy, I think the online wallet is safer than the wallet ofline. if we send bitcoin from our wallet to another wallet online then it is very easy process of delivery.
Online wallets are are unsafe for a large amount of Bitcoin. The best cold storage is hardware wallets. Most of my holdings are easily traced since it came almost entirely from coinbase.