I hold some of my BTC online to use to buy games and some gifts that I can find cheaper here than when using other payment methods but the main reason is because I hold them for a price increase and waiting for the market to go positive.
That is quite good. But it is not not to have too many in a online wallet. It might be hacked by somebody.
You are right that it is not good to keep our money in online wallets , i.e a number of people are complaining on this forum and on some other places that zapo has started to freeze their accounts without any reason. In one of the post I read that a person is saying that he is using his wallet every day and one day when he came there he found that he is unable to login there and the asked for documents.