A very good TIG welding technique for pipe and a few other round shapes is walking the cup.
But its good to be also be able to freehand.
Sometimes there are obstacles that prevent walking the cup. For those occasions being able to prop with a tig finger can help.
Other times, a part has smooth machined surfaces and job specs will not allow the scratches from the ceramic cup.
Walking the cup is primarily a technique used for pipe welding but I have found a few other uses for it like a run of 50 round parts I welded in my shop a while back using a turnrtable