Did blackout curtains actually improve your sleep?

put blackout curtains in my bedroom a couple months ago mostly because the streetlight outside was driving me nuts. it wasn’t even that bright, but there was always some light coming through the window. my sleep wasn’t terrible or anything, i just had this annoying habit of waking up around 3 or 4 for no obvious reason. figured i’d see if making the room completely dark helped.
after the curtains it got noticeably better. the room is completely dead dark now, like disorienting dark when you first wake up. took a few nights to stop feeling weird about it. but i'm sleeping through more consistently and the early wakeups dropped off a lot.
what i can't figure out is how much of that is actually the darkness doing something versus placebo, or just me paying more attention to sleep because i made a change. i track my blood sugar pretty closely so i know that side is stable. diet is the same. activity level is the same.
curious what other people noticed going from a lighter room to a darker one. did it make a real difference or was it one of those things that sounds good but didn't actually move the needle. and if you've gone back to sleeping with some light for whatever reason, did the difference show up fast or take a while.