You’ll never regret buying your Dremel! The flex shaft is extremely handy also.
I bought the router attachment to go with mine, so cutting small, neat holes (EX: turnout throw rod access holes) in wood or other fairly soft materials is easy. Just drill a starter hole, and away you go.
I’m glad you took the safety warnings to heart, those cutoff discs are dangerous, so NEVER, NEVER, NEVER use them without safety glasses!
Also, be aware of where any sparks will land if cutting metal. You don’t want to burn down your layout! Sometimes covering the target area with a slightly damp rag or paper towel helps.
I sometimes cut N scale rail with my Dremel. I hold the tool so that it is over the piece of track I want to save. That way it sort of undercuts the rail and the two top edges will butt together. The little gap on the bottom edge gets covered by the rail joiner anyway. I also use sidecutters to cut rail. They work well, and they’re less dangerous.
Safety glasses are a must. I’m even considering a face shield for when I use cutoff wheels and tiny drill bits. The thought of stitches in my face doesn’t appeal to me. The last time a cutoff disc broke on me, half of it jammed in the rail, the other half hit the wall on the other side of the room and has never been seen since.