yeh they are there for a purpose but the problem is that none use melee attacks its pretty rare to see rangers use melee weps and shield but altought ranger is a rogue like class.
idk why they revamped it like it is now i havent played ranger before like it was but i think ranger are still good.
i dont use melee attacks at all but it can be usefull if you swap quick weps and use some attacks with hotkeys then back 2 range again
sometimes i like to switch to melee, but just for fun...
eg, yesterday in ardashir i did 2 fatalities with sword, against the trash!!
other than that, the only use for melee combos, when you're in group, is to apply a cc (shield bash mostly) every now and then...
ofc i use upper and lower on all my attacks is taht what i should do or just lower or upper on some attacks?
lazy answer: yes
long answer: it depends on a lot of factors...
pen. shot: upper attack reduces the cooldown, so you may skip it if you know you won't need it again soon (eg, the mob is almost dead, and you will have to wait for the next pull)
bleeding puncture: upper attack increases the duration of the bleed, so it may not be needed if the target is already low on health
linebreaker: upper attack increases the power of the knockback, and it's not always needed
quick shot: sometimes you may want to use it partially unbuffed, to be able to use it before the mob dies
armor ripper: upper attack applies phisical torment, but if the debuff is already at x5, you won't need it, unelss you need to refresh the debuff