Nelson Cruz might play Right Field for whoever ends up with him, that doesn't make him a right fielder. At this stage in his career is as a DH.
Last year Nelson Cruz was worth 11.3 RAR batting, -2.9 base running, -4.3 fielding, and had a positional adjustment of -5.4, if you throw in the replacement adjustment he came out to 13.8 RAR or 1.5 WAR. He was barely above league average as an outfielder and given that he's slower and older he's only gonna get worse out there.
I wouldn't want Cruz desperately either but for a team that is now actually coming close to being a .500 team, it does make sense. Look at how much value guys like Beltran still carry because they've been able to string together good seasons after career-altering setbacks. If you can grab one of these low-value guys for a nice price and actually become competitive in the process, go for it!
Nelson Cruz doesn't want to be paid like a low value guy coming back from a set back. He wants to be paid like an established star. His market worth is about 1 year and $8million dollars, you could reasonably give him something like 2 years and $16mil total and not have it be a colossal waste of cash but once you go beyond that you're just wasting resources.
Comparing Nelson Cruz to Beltran is silly as well. Nelson Cruz has had 2 seasons in his entire career where he was worth more than 2 WAR and both of those seasons he had fielding numbers that are total outliers for the rest of his career.
Also I think a lot of you guys need to read up on something called "The Marginal Value of a Win":
http://blog.philbirnbaum.com/2010/04/marginal-value-of-win-in-baseball.html is a decent primer. The basic idea is that teams as far away as the Mariners should not be willing to pay as much for marginal upgrades as a teams who are closer to titles like the Dodgers or Tigers. That extra half war that Nelson Cruz might present over some AAAA guy in RF isn't really as valuable to the Mariners as an extra half win would be for say the Cardinals.