Sushi123 you may have found it easy, but I would have found it very tough indeed to be seperated from my baby at 11 weeks, it's not something I'd do if I could avoid it and I know lots of mothers feel like this. If you ask mothers when they first left their babies, it ranges from a few days to a couple of years!
I left mine with a family member at 5 months for an evening I'd arranged before he was born, but that was difficult and I didn't do it again till he was 1 (for New Year's Eve) and apparently he was up all night screaming for me.
Many mothers just don't feel comfortable leaving their babies when they're so young. It's not as simple as it being a choice.
Yes it's doable, and it worked for you. But for many it would be a huge issue and not to be underestimated. If you didn't feel like this and your baby was fine with it then maybe it's hard to imagine, but it's pretty normal for mothers to feel that wild horses wouldn't drag them away from their baby when they're so little (and it's also normal to be able to leave your baby - neither is the "correct" way. Mothers and babies are different!).
Did you breastfeed?
Putting either of my babies in nursery for a day a week at 11 weeks when exclusively breastfed would have been tough.
Persoanly, I found expressing a real pain, I never really got the hang of it and to need to do it all the time would be a huge extra stress. Yes combi feeding would be an option, but not everyone is comfortable givng formula, that's an individual choice that should be respected.
I wasn't saying nursery for a day isn't doable for anyone. But the way you presented it, had I not had a child yet, I might have though "oh, she did it so it's an option, I'll do that" and then find that the reality is that yes, it's an option, but such an incredibly hard one that simply isn't worth the stress.