They're great...just not for math. Use a decent pencil instead, like a Graphgear 1000 and some HB lead.

Pens are fine for math. I often used a fine point gel pen in college. However, you have to have a high degree of confidence in what you're writing. If you make a lot of mistakes (either actual mistakes or just wrote down something incorrectly or with a misspelling), then pencils are definitely better.

Only if you make sure to have the right kind of lead, eraser, and paper.

A crossed out line followed by a legible one is better than a line written over gray mush. Or mush from papers rubbing against each other over months.

But pens also assume that scratch space isn’t a limitation.

Pens seem crazy until you get used to writing that way, then you can’t turn back.

I got to a point where I would just write down all my solutions on a final paper to turn in for my math assignments.

I did everything in pen, bc of handwriting issues and pencils. I simply burned through sheets and sheets of paper with my preliminary work- then copy everything to something both legible and presentable.