Would you leave $3000 in cash sitting out on a table at a hotel? No? Then why leave a small, easily concealed item that's worth $3000 out on a table?
I lock my laptop up. Sure, it's possible to cut through those locking cables, but it's not easy. I figure it's the same principal as The Club - it will not stop a determined professional, but it will slow them down just enough to make them move on to the next car that doesn't have a Club.
Likewise, if my laptop is locked up to something, a thief who is looking for a quick, loose item to grab and run with will not be able to simply tuck it under his arm and run out.
No matter how many people post, "I stuck my head in the oven while it was on and didn't get burned!" it is never safe to stick one's head in the oven while it's on. The same goes for leaving small, portable, easily concealed valuables such as electronics, jewelry, cameras, or cash simply lying about unsecured in a hotel room.
Lock 'em up, friends. Before they walk away.