but a lighter pick can have great tonal qualities.
and if you look at famous pick players, they use picks between 0.60 and 1mm, the most common is the yellow tortex in 0.73...
talking about strings gauges, in my opinion is mostly about feeling, not tone, BUT with lighter strings you can lose some dynamics.
I've used 30-90 strings for years as I've used 50-110. once you get used to the gauge, with a proper setup, the hands won't bother.
as mentioned above, the only real difference is in the dynamic range: with light strings you can't get higher dynamics for a simple physic principle: if the string is to flexible, when you pluck it harder it bends too much, following the plucking finger, oscillate too widely and could not give you more volume.
I describe it like having a limiter always on.
with heavier strings, the force you put in your fingers is better transmitted and the string can give you more volume.
is necessary? not always, so It's a matter of personal preference, style of playing...
usually I play with 45-100 (or 43-110 Rotosound) because I like medium gauged strings, and when I use smaller gauges, like on the Hofner (with Pyramid Gold flats), I like tight strings.
FE: the La Bella HBB2 set is too flexible for my taste; the Pyramid Gold set is perfect.
when I used 30-90 strings I liked them, but when playing harder I fatigued a lot with the right hand.