90% of how I find people on social media sites is through other people. I go to the page of someone I like and I see who they're following and check out those pages. Without the ability to do that each person I follow is like an island that I have to find individually by searching for them. That's why it's really important, imo, to not only be able to see who people are following, but also to go to a user's page and see a little "followed by [these people] who you follow" note.
oh and ofc it should be an opt-in feature, if you don't want people to see that info on your page you don't have to show it
This specific request already exists here: https://help.antisoftware.club/support/discussions/topics/62000183135
And since it's relevant, a request for a "follows you" notation has already been submitted and turned down: https://help.antisoftware.club/support/discussions/topics/62000183206