It’s a read just like anything else. The reason it’s hype when you guess correctly and neutral duck, is because at higher levels throw attempts aren’t as predictable (and guessing wrong is really bad). Like in KL most throw attempts are easy to scout, but good players will be more unpredictable and they will also fake a throw attempt into a mid into a bnb or just big damage. Fake throws into shimmy or into lows/mids have been in fighters for awhile now, but they are cooler in MK11 when you take KB’s and how good throws are into consideration.
Also, you can do this with neutral duck. Which if this is ever done in tournament it would be super hype: