If it's really only a point or two, is it even worth talking about? Again, this is just my opinion/experience, but I'm cautious about not encouraging perfectionism in cases like this with my kids. If you mean it's a point or two on the Ts and a point or two on the Is and...and...and..., then it all adds up to a big loss of points, that's different.

Yes -- the never-ending balancing act.
At this point, I think I might be willing to trade a little bit of perfectionism in exchange for a little less I-don't-give-a-dang-ism.
The majority of the quizzes in his class are only 10-15 problems, so missing two on those is automatically a B. Personally, I'm fine with that B -- but it frustrates me to see him give up the points purely due to rushing. And that same habit of rushing gave him a very smelly "D" on a couple of longer chapter tests because he didn't read & follow simple instructions.
Because of these, I started something different with him on his weekly homework assignments: before answering any questions, he has to underline the key element of the instructions & review *that* with me first. We've only been doing this for a handful of assignments, but it seems to have eliminated a bunch of the silly mistakes.