probably a lot less performant than doing it the old fashioned way. sometimes that matters. you should have the non-grid non-flex method half committed to memory. abusing flex or grid to save 2 lines of code is not a great practice, and having only one child element is usually a pretty clear sign that flex/grid is the wrong tool for the job

at the end of the day though do whatever you want, in fact why not just write a javascript function to recenter it every frame at 60fps cause 99.9% of the software 99.9% of people interact with is pure shit made by developers who don't care for users who don't care.

we live in a slop world, made by and for slop people who love slop. can you tell i've been awake for 30 hours? anyways...