If you're writing code and you get a review request and ignore it, you are literally preventing value from being shipped while you work on making some abstract idea a reality.
Usually, the code review is the very last step before value becomes available to the business. There is absolutely no reason to delay a code review in this case, none, whatsoever.
Even if it isn't the last step, you're delaying the chance for a developer to continue working. More often than not, when a PR is submitted, there is a period where the submitter is twiddling their proverbial thumbs to prevent context switching from a reviewer.
So, delaying a review prevents value from being available and reduces overall developer productivity for the entire team.
Or, keep working on making an imaginary idea into a real one while someone else's already built idea sits there wasting money.