I have come across couple of posts in recent times where members have been trying random wallets and losing their funds. The reason which I assume is, there might be an offer for downloading the wallet(airdrop) or they were part of a bounty program or they might want to try something new.
It's not that these bounty participants are using random wallets. There are coin projects that do have their own standalone wallet so it's part of the requirements. Participants have no way to receive their rewards on other wallets. Of course, these people I think will not use the wallet for storing purposes of other cryptos as I mentioned, it's standalone or in case of multi-wallet, I doubt they will deposit some money here since after all, why not just directly send their funds to a trading platform where that coin/token is listed if they want to trade with it.
Generally, people have different preferences. As recommended, be familiarized using a non-custodial wallet and just used exchange service or web wallet if there's a purpose like buying or selling for convenience.
