What do your rims look like?

When rims were flat across the top, you could drill them out with no problems what-so-ever, I have a hand reamer that I use for that and it's a piece of cake.

Many rims today, maybe most, have a deeper vertical profile. That requires a little longer valve stem. If your valves are too short, it's hard to thread a hand pump chuck onto the valve especially on Schrader valves. An air compressor Schrader chuck just presses against the top of the valve so it's not affected. If you normally use an air compressor to inflate your tires (the only reason that makes sense to me for making the change), you might not notice until you have a puncture on the road and find your hand pump won't fit well enough to re-inflate your tire.