As far as I can tell, the annual return stays at 17.66% for the duration.
Is there any drawback I'm missing?
Why don't people just buy Cryptos that they can stake?
Honestly, people don't take this staking option as the best thing to do because it was too risky in the first place. Whatever happens to the exchange where you stake your coin, you will also suffer possible losses. If you are very concerned about the safety of your funds, you will not do that but instead, just keep it in your personal wallet.
They offer a 17.66% annual return. It was big enough to consider but I'm not sure how reliable it was because based on my experience the usual offer won't go far above 5%.