I have a water valve that is corroded and I hired a plumber to come out to
repair it. When he finished the job I noticed he attached a copper pipe
section to the original pipe that is galvanized. I thought I have only seen
copper pipes used indoor behind walls, and it seems the copper pipes are
kind of weak...when I asked him he said it's the same but something makes me
uneasy about it.

This is the main 1" pipe that comes into the house. Using the think copper
pipe just does not seem right to me. May be it's just me.

MC