True, if you're going to be using the phone all the time, get the subsidy.
However, I've paid full price (and/or bought phones off eBay) so that I'm not required to pay for a data plan for a phone until I actually use it.
(Requiring a data plan for subsidized smartphones is something that came along with the iPhone. Didn't have to before then. Gee, thanks, Apple and ATT.)
That way, I have the phone without obligation and can swap it on or off my data plan number any time I want.