I don't think stashing your bitcoin is a great idea. Putting your coins in a stash means giving up your ownership and custody over it because you permit the exchangers to have the authority over your funds. Hence, when hacking happens, your assets aren't safe. There are numerous incidents of hacking already reported with these exchangers and wallets. I suggest to be wary and always double-check where you are putting your hard-earned money/coins because it's not easy to make money nowadays. Reassess if the risk that comes along with stashing your money is worth it or not. For the interest that they will give you, will it be okay to put your funds just for the sake of having your money grow with them? If yes, then go ahead. After all, there are several exchangers that offer pretty much decent interest over time. If not, then don't do it. It still all depends on you.