They seem to be removing or hiding features for more advanced users.

I am big user of saved lists where I keep all sorts of stuff from recipes to various ideas for the home I am preparing to build to financial or parenting advice to programming tutorials, etc.

Now on mobile there is no way to save it to the playlist. The only way is when it is still in search results (but you can't get back there after you clicked the video or from history!) So the best way for me to do it is to get myself to the laptop and save it from there.