To really purchase BTC and ETH is very easy, some​ wallet even allow you to purchase with your credit card and deposit directly to your bank account. But it's not that easy to Exchange your​ altcoins for fiat. Is it the fact that altcoins are scattered in exchanges and you have to register in different exchanges that support the altcoin you want to trade or the fact that sometimes the price changes really fast and if you sell high it might take some time before your order get filled. I really find it really stressful/frustrating after all we went through alot of stress while participating in airdrop/bounty.