He's a more athletic version of Jason Hatcher and a bigger version of David Irving. Marinelli, like Seattle, seems to like those rare 6'6" 3Techs versus the 6'0" Aaron Donald version of 3Techs that many teams prefer.
His stats and lack of production will be will be what determines how bad he sucks. Back-up QB is like being a left-handed pitcher or a 7-footer. You can have a long career if you are in the right situation.
The whole UDFA is overblown here. Romo had no business going undrafted and was/is magic. Miles Austin was a short-time success. A lot of kickers are UDFA. La'el Collins was a freak situation.
Also, the thing about Jerry outbidding other teams is exaggerated. Teams can offer just as much, it's...
North Dakota State is a Division 1 team that won straight 5 straight FCS Championships, including wins over several FBS teams. They aren't really a small school anymore.