Just saw a show and noticed the pros are using a split ring. I have always tied on to the lure directly.

Clip or snap for me in most cases.

I started using norman clips not long ago, and they work fine so far.

Every crank I see comes with a split ring on the line tie out the package

Using a split ring gives the crank freedom to move more naturally.

The line can get worn out by the 2 openings of the split ring. I leave the ring on and use the snap or clip. If it is shallow cranking I will use an elongated split ring so the knot has less chance to get damaged by the openings of the split ring. And not using the clip or snap in shallow cranking elimantes something that might get hung up.

Speed clip; no split ring

What about deeper diving baits? Say 12-16 feet, same setup?

If u tie ur knot where ur line is in the side of the split ring that doesnt have the split u get more action out of the lure Plus u wont wear ur line.