Coins should always be considered in a safe storage, there are lot of wallets and platform that could be used to hold coins, both of this has good side and bad. Where will you choose to store or hold your coins, in a close source wallet (exchanges) or an open source wallet like electrum and Hodler wallet?
Depends on the coins I should hodl. If the wallet I'm using has the coin I wanted to hold then I'll use that coin. If it doesn't I'll find a wallet or exchange that has that.
Maybe limited wallet or maybe not all wallet that support a token or maybe a coin to save in there. So people use exchanger to save their money and then must take all risk behind it. So maybe in future there are a lot of e-wallet that can support everything.