So I Signed Up (or Applied) To A New Affiliate Program...

[ecchi]

IMHO:
When I send hard earned traffic to a sponsor I expect them to be converting it as fully as possible. To me the line:

Can you provide some history of traffic sources and also if you have sent traffic to any sites in the past?

Says "We are not very good at converting, so we only accept the easy to convert stuff". So I would not use them because I would feel they are not making best use of all the traffic I sent them.