I think stabilising, is knowing what your pattern of baldness is going to be. I. e, if all your brothers/dads/uncles etc were norwood 6 at 30, chances are, but not always, you'll be the same.
That helps when planning your ht and looking at the availability of donor hair for future loss. No point in going for a really low hairline, then running out of donor options at a later date.
The meds slow down or stabilise the progression.
Personally, i'm not keen on taking finasteride, but might give it a go to see if i'm a person who gets sides.