This is basically a form of chunking. Instead of just trying to “play fast” and hope for the best, you’re now basically playing a repeating sequence of hand movements. Personally I tend to accent the first note of groups like this and you can see it in many of our slow motion examples. It has been pointed out to me a number of times that the first pickstroke on a lot these phrases is actually visibly bigger than the others, even on single string lines.
I also find this helps gauge tempo. If you listen for the unit, and not the individual notes, it’s a lot easier to hear when you’re speeding up or slowing down. If I do an unmeasured tremolo, I have no idea how fast I’m playing unless I film it and count the notes. And many times it’s not at all what I think it is. But if I’m playing repeating units, I know exactly what speed I’m going at all times. I think this is why some players who only ever did tremolo work for speed have not-so-great hand synchronization. For me it was the opposite - I never worked on tremolo and only ever did synchronized / chunked type practice.
Are chunking accents a bug or a feature? I don’t know! I used to think it would be a negative to have unnecessary accents in your playing. But I think in actual practice you can dial them back so that they are not overwhelming your dynamics. And if it helps you get lined up to begin with, maybe it’s worth it.