NHL is one of those games where it could entice a fringe hockey fan to get the game. Madden, most of their sales were people that were gonna buy it regardless. Hockey itself doesn't have as big of a hardcore fanbase, so any tool to help bring in the fringe fan would still be used. I don't think its because of EA Access, but because a demo simply wouldn't add sales to Madden.
That's my opinion anyway, someone else might think I am talking out of my ***, but it makes a bit of sense from a business standpoint to me anyway.