To put it simply: All upvotes done by the @musing account are all done manually.
I understand though why some people here have thought that it was done automatically as other platforms like Steemhunt employs a somewhat automatic upvote system that rely on one's user score and total score received by one's comment. If I am not mistaken, only the top 100 comments receive some sort of upvotes/rewards.
Also, seeing that there are only 4(?) musing curators and today is the weekend, then most likely these 4 have quite some fun last night (Good for you guys! XD) or they may have prior personal plans for today so they can't curate atm.
I think my point here is: Give the curators a little break once in a while and that they will eventually get back to curating once they have some time. XD
Although I also get you as it is indeed a little wasteful for the account to stay 100% for some minutes or hours. XD
The simple answer is Musing.io team only do manual curation and all team members are on-leave currently.