The US prevents Pakistan's F-16s from carrying nuclear weapons. According to the article above, the planes won't allow any unrecognized weapons, and the sale stipulations permit surprise inspections and round the clock video surveillance of the aircraft.

So it's really not hard to understand why countries would be interested in the Gripen because they can own it outright and do with it what they please even if it's inferior to US weapons because the US weapons they'd be going up against aren't flown by the US but by other countries with similar restrictions on them.