I think its better to dequeue it with PHP snippet so that everything will be removed and the related code will not load.
OK. Do that then. The difference in the site's responsiveness will only be noticeable in your imagination. But whatever you're happy with.
But also take into account ...
1. The Snippets plugin's impact, if you use that for the snippet.
2. The impact, hassle and/or possible overkill of using a child theme for this one little trivial thing, if using the snippet in functions.php
3. The hassle of editing the functions.php with every theme update if not using a child theme.
VS ...
The relatively low impact of a simple "
Set and Forget" CSS "
snippet". PLUS the fact that it's operating in the back end (
WP-Admin) where it has no impact on the front of the site's responsiveness anyway.
Up to you. But I'd Google "
The KISS principle" if I was you.