Why is piston knurling all the rage on YouTube?

[Woody500]

back a long time ago , I bought a basket case street hemi, 66 belvedere , the block had been bored .030 over before he bought the pistons , was way too loose , I knurled the hell out of the pistons myself at a friends machine shop , way over did it (read heavy) .
Then did my best to sand the hi spots off from the tips of the knurl , ( to make it last) ,while trying measure them , measuring the knurl was time consuming and a ***** but I got it done .
It worked very good to great , ran good , lasted till I sold the car due to hard times , I beat on it every time I drove , and drove it to work every day till gas got too expensive for it ....

Have used a file to fit knurled pistons(much easier to clean) when rebuilding old Marine Engines, at my boat shop, and also Military engines, neither you could get new pistons for, when I worked at Ropkey Armor Museum. Only used a ball hone too.
They usually are tight when assembled, and some times had to use 12 volt to start a 6 volt system and 24 volts once for a 12 volt system. After a few starts normal voltage was all you needed.
Can't pull start a boat, and the Military one was onboard genset, M48 A1 tank.