Hey dude, I find that long taper bugpins are great for smooth shading but are definitely not good for lining. At least not with my machine, but Im guessing its a general thing that bugpin long taper arent very effective for solid lines or packing especially.
I put bugpins and long taper in the same category because a smaller diameter needle of bugpins and the finer tip of long tapers are basically designed like that for the same thing. Smaller "pixels" per say, for a higher "resolution" of saturation. Which means you need more needle penetrations to cover an area so that translated to smoother application.
But that also means its harder to saturate so not efficient for lining or packing.
If anyone thinks Im talking out of my ass, please say so because Im just thinking about this in a logical way from how the theory is resolved in my head.