I don't see how it can be more accurate since there's a fixed connection between the two,
but I agree on the pressure release at least

I think I'd just pushed one lifter in to do the same
(to let it go and air lock the piston in place once TDC is met)
but removing or at least undoing the spark plug is more convenient for sure.
for actual piston position it doesn't make any difference..
In fact it's likely MORE precise to look from below than from above, since you can watch the conrod passing the apex ..
But afterall, since that's not even a full tooth on the cogwheel it doesn't make a difference for reinstalling the camshaft.
'sid