Do NJ's maternity benefits apply to NJ residents or NJ workers?
I am a NJ resident but work in PA. I have a short term disability policy through my employer that covers 6 weeks at 60% pay. I would love it if I was covered by NJ's benefits, 4 weeks before and 6 weeks after at 60%.

I understand you would love it, but I don't think so, since as a Pennsylvania worker, your employer was not subject to the law and neither of you contributed to the fund.

At least you were smart enough to enroll in the STD plan through your employer when you had a chance.

Aren't I contributing by paying NJ state taxes?

Nope. The unemployment/disability programs in NJ are funded by employer and employer contributions to the fund specifically. Not income taxes.