I don't think you can part-time homeschool this way, i.e., by just
keeping her out of school at random. However, lots of districts allow
part-time homeschooling of a different sort, which involves the child
doing certain subjects at school (with bright kids, that's often often
the nonacademic ones) and certain others at home. That might be ideal
for you, if your district allows it.

I agree with your perspective to a certain extent. I don't find school
to be a scintillating environment that my child shouldn't miss out on.
I also have a child who is not learning a lot *academically* at school
and who could undoubtedly do just as well on tests if he missed a day
of school a week or more. And, as I would generally only want to take
him out for enriching experiences, I would argue that his education
would benefit from the absences.

But I also sympathize with the huge organizational feat that school
is, at least in my son's very large, rigidly structured school. Every
time he misses school, work is created for his teacher. As far as I
can tell, she is not at liberty to let him just miss work, even work
that she knows he has mastered; she has to make sure he gets it all
done at some point.

Also, there are rules on the books that you need to watch out for.
Might they come after you? Sure. School administrators tend to believe
that they know what a kid needs much more than the parents do. Letting
a child miss school for "no good reason" more often than very
occasionally is tantamount, in their eyes, to not getting him/her
vaccinated: totally, wildly irresponsible. So do be careful.