If you know how to value time you don't say stuff like this: the point of time is to live life meaningfully by your own standards (which may or may not align with society's standard)

Our brains all generate relatively the same amount of happy/sad chemicals, so it turns out the satisfaction of winning a nobel peace prize and the satisfaction this person feels fixing their dumpster dived keyboard can only be so different in magnitude.

It's not like doing universally meaningful things unlocks some kind of super-happiness, so there's no reason to shy away from "unmeaningful" things if they bring you joy.

I assumed the point was that your comment "dumping a membrane board in the landfill like OP apparently does" was a misrepresentation, as the author was doing the exact opposite of dumping the keyboard in the landfill!

Whether this represents a good or bad use of one's time, who can say. Some things, people do because they enjoy them, even if the activity doesn't make complete economic sense.