The point is that if the cutscenes are the most important aspect of a game it might not be the best of games. Compare it to heavy rain if you will, it does not focus that much on actual gameplay rather it shares more similarities with movies because the gameplay seems more like an afterthought than the main focus of the game.
While the Mass Effect series aren't as extreme they can easily be compared.
One could also draw parallels to Planescape: Torment, even if the story isn't nearly as well told in ME and PS:T does not encourage much combat at all. The problem here is that the quality of the "epic" cutscenes of Mass Effect never reach even the lower standards of film, neither in acting, writing nor cinematography. You just can't compete with proper films, but you can do some decent writing in games which PS:T did.
Finally, if you spend half the game hiding behind chest high walls and shooting stuff it better be good, sadly Bioware does not seem to realize this as evident by the many dull and repetitive encounters during the games. Mass Effect is a Mona Lisa painted with feces, it's nice to look at from a distance but it stinks.
