Likes get completely lost from me as an user. I cannot retrieve what I have liked one, two years ago or even a few months or weeks ago. I can simultaneously bookmark but doing two actions for the same thing is cumbersome, and bookmarks can be kept for private starring of an item or "to be read later again" or "personal reference items". Likes are always "public" by default, and that is great!

There is of course Matt Becketts plugin https://elgg.org/plugins/1200643 which almost serves the desired purpose but it works with Elgg 2x and with 3x it gives fatal error, and looks like its abandoned. If a small amount of code from there can somehow be incorporated into core - it will be very useful. And the users upgrading from 2x to 3x will also not lose their important list of Liked contents.