Actually that's how all dashes work
with some exceptions in those dashes which are unstoppable (All CC will have no effect before the dash ends) and some dashes which are specifically stopped by any hard CC (I can only think of one such case
E but there might have been some I forgot about)
The thing that makes Tristana's jump special is that it is so slow... with 0.5 second delay before it begins and it has a pretty long range but not that high travel speed making it so that the dash takes a while to complete making it so that most CC wears off before the dash is complete
While most other dashes have much lower delay and travel time making them much better for avoiding getting hit in the first place