Is this intended to free up memory then? Increase the effective size of the mempool by screening out ordinals?
Discussion
Unfortunately I don't think it will save you disk space. Its more about your node not participating in recognizing and broadcasting ordinals transactions.
You can read more here: https://thebitcoinmanual.com/articles/what-is-ordisrespector/
Nope, you'll have to prune the witness data yourself if you want to clean up space