Help me make some clarity on Binance spot trailing stop?

Hi there guys and thanks in advance for your help. I am trying to figure out how does the trailing stop work.

In my mind, I want to set it so that I can maximize my profits. Lets stay my activation price is 10 with a delta of a 2%. I would expect that when price hits 20, then goes down to 16 (2%), I automatically sell at 18. Instead, Binance makes you input a LIMIT. And the order will be executed at that limit. What's even the point of that ? For example:I buy at 8 and set activation price at 10. with 2% delta and a LIMIT of 8. If price hits 20 and then goes down 2% my order is sold at 8 which is the limit price.