Looking at Google maps, it looks like Whistler has more courses than Banff. I'll be in Banff in early August and will check out the area and update this post then.

Whistler has four great courses right in Whistler. Lake Louise does not have a golf course, and Banff only has the Banff Springs course, one of Stanley Thompson's great designs. In the Banff area, one has to drive 30 km east to get to a few golf courses. Canmore has Stewart Creek, Silver Tip, and Canmore Golf Club. Venturing even further east, the two courses at Kananaskis are re-opening this year amid much fanfare after being closed since significant flooding in 2013.

If you don't want to drive much once you arrive at your destination, the courses at Whistler will serve you very well. If you don't mind driving a little bit, the courses in Canmore and Kananaskis will be worth the drive from Banff.