Generally, on many "performance" pistons, they have holes that are drilled from the oil scraper ring, to the pin bores.
There are also a few that just allow oil back onto the underside of the piston/rod.
The holes that are drilled into the pin bores "pressure" lubricate the pins at that point. A small hole drilled in the top of the rod so the piston pin is lubricated is also a possible route so it's splash lubricated there as well. (If you have that, make sure the bronze bushing on your rod small end has the correct lined up hole to allow the oil in, or it will not work.)
As the piston descends on the intake and power strokes, the oil rings scrape the bore walls, and the oil is forced through the holes, around the piston pins, and splashed into the rod bushing. (If it has that feature.)
This is also a great transfer of heat from the bore walls and pistons, into the oil, and that hot oil falls back into the pan, where it can be pumped back out of the engine, cooled and then returned if you have the right setup.
The oil squirters just increase the amount of cooling. (The stock rods also have squirter holes in the shoulders, that spray oil on the thrust side of the bores, further cooling and lubricating a potential wear area.)
It's proven you do not have to have this stuff to make a powerful 7M, but unless you replace parts with ones that don't have these features, I would not remove them unless you have a good reason. (Oil pressure is a good reason, but I'd increase the flow, v/s reduce the amount of volume loss via things like the stock oil squirters. Getting rid of the stock oil holes in the rod shoulders is a good idea, in that it makes the rods stronger in my opinion, and you have more oil pressure at the rod bearings without that "leak" source.)
