CSS with Element hook instead of simple CSS plugin

Dear Team,

I have a question regarding speed optimisation and CSS good practice.

I uninstall the plugin of Tom called simple CSS because my clients are worried of the fact that it hasn't been updated since long time (even if it still works perfectly).

Hence as a replacement I code my main CSS inside my child theme CSS file AND when I have CSS for specific pages only, I create an element hook and insert my CSS styles inside a <script> tag.

Is this correct or wrong purely in terms of good practices and speed?

Thanks for your guidance. Adrien