Another old school sewist here who learned to sew using scissors and shears.
I use a rotary cutter for patchwork and for cutting any long strips of binding etc but my reasons for using scissors include:
1, I don't have a big enough cutting surface - my 35" x 23" mat is nowhere big enough to cut out garment size pieces.
2, Cutting part of a piece, moving the mat and then cutting the rest would likely result in inaccurate cutting. It would also interfere with laying out the pieces especially when tight with fabric, especially if the pattern pieces are not pinned down.
3, For me freehand rotary cutting is not accurate. In last week's GBSB did you notice how one of the contestants sliced off a quarter of an inch of paper pattern, so presumably a quarter of an inch from the fabric, when cutting a pocket?
4, People who use rotary cutters tend to use weights and not pins. How do they prevent the pattern from moving around?
5, Cutting proper outwards notches is very difficult, even with a small diameter rotary cutter. Two reasons why I was taught to cut notches outwards, as I always do. Snipping inwards effectively removes the seam allowance so you have no wriggle room if the garment is a bit tight and needs letting out a little. Also the tiny inwards notches are easy to loose if the fabric frays. Remember the last series of GBSB where a couple of them had two left sleeves! That was all down to cutting inwards notches and loosing them. Sometimes my outwards notches are extra large but I don't loose them, and they get trimmed off when the seam is neatened anyway.