Why do people use CoinBase in the first place?

When we're using Bitcoins, we use it because of it's decentralized nature and complete control over it (and not on intermediaries like bank/government).

So why then are there still people who use CoinBase as their "wallet" to store their coin, leaving this intermediary(CoinBase) to decide what they gonna do in case of hard fork?

Isn't using CoinBase against the reason we use BitCoin in the first place?

Putting your asset at the mercy of others?

Please share your thoughts...