i think they could also add an additional option to keep hidden or show a button with "invite to play" under the "mini profile" (the one we can see "on mouse over" the avatar-profile picture) and "main profile page", even if the user has or not a "public profile".

i dont like to have my profile public, and wouldnt like to make it semi-public and share it with anyone else, to avoid spam and useless (at least for me) comments in my main profile page. but i would be ok with playing sometimes with others if i could keep two types of contacts separate: "close friend + family list" (so i can keep this private too) and optionally private a list of "other players".

unless something that allows me to keep my "close friends + family list" hidden and private, as well as my personal profile from others, im not ok with playing with anyone else: imo it has more downsides than positive aspects (and also most games i played and still play are "single player", lol).

Users should be able to customize all those options.
Even when play only single player games, sometimes we like to share experiences with others.