Throwing weapons. Pointless?

[Skies]

Pretty sure the TP gained from using throwing weapons is less than that of AA's, and you're usually interrupting your AA to use a throwing weapon anyways so you're lowering your TP gain even more.

Nope, AA is not interrupted by weapon-throwing, in fact essentially nothing short of a long execution animation will interrupt your AA sequence.
However, in relation to 'how is this fair to archers' it's pretty simple, my friend. Archers can use throwing weapons as well, giving them a (perhaps needed) secondary source of TP income. Not like i've tried that yet anyway, I haven't levelled ARC and my LS is kind of slow to get moving, but evenso.