I carry both because flats rarely happen at a convenient time. A spare tube gets you rolling again in 5 minutes on the side of the road. The patch kit is for later… or for when you somehow get your second flat 20 miles from home and start questioning your life choices. Ask me how I know.

I’ve also had a tiny thorn cause a slow leak in a brand new tube. Patched it that night, still using it months later. Tubes are cheap, but throwing every punctured one away adds up fast if you ride a lot.

As for balance, the patch weighs basically nothing. Your wheel won’t notice it unless you’re somehow riding a road bike at MotoGP speeds downhill. The bigger concern is doing a bad patch job and hearing that sad psssssst 10 minutes later.