Address is pretty standard for anyone accepting payments.
As for employer and occupation, we are legally required by the Federal Election Commission to do our best effort to gather the donor's employer and occupation. Doesn't have anything to do with taxes.
Ahh I see. I know some processor now forgo the requirement of addresses, eliminating alot of fields and barriers even more. It may take quite a while to get used (and feels scary too).
As for employer and occupation, we are legally required by the Federal Election Commission to do our best effort to gather the donor's employer and occupation. Doesn't have anything to do with taxes.