The biggest issue that I can see is that most bullets intended for use in a 9x19 loading do not have a cannelure, and case neck tension for normally-size 38 Special brass will be inadequate to hold the bullet without a crimp.
Since I'm shooting cast lead .356 bullets, I roll-crimp the case mouth right into the lead bullet, and as a result the bullet is locked up pretty well. Not giving a firm roll crimp may cause the bullets to pull rather dramatically under recoil.