rebel-
It is not so much the utilization of needle bearings. The reason this is done is for large base circle camshafts which have bigger journals requiring specific bearings (both roller and conventional bearings are utilized for the big base circle cams). The proper application of the large base circle cams requires more than a simple lesson in camshaft profiles. The large base circle cams are utilized by many class racers, such as Super Stock and Competition eliminator plus, many Top Dragster, Top Sportsman and all the professional categories. There are many who will say there's no advantage and for some I'm sure that was true. However, when you check with the top qualifiers in those performance oriented categories you'll find most if not all use the big base circle cams. Like so many other things in Class racing you just can't bolt one in and have an immediate improvement. I was on my 3rd different grind before I saw meaningful improvement and those cams are much more expensive than a conventional roller cam. For those who are not Class racing there is a lot of lower hanging fruit to grab for getting more performance out of your motor. I hope this helps, good luck!
Bill