Movies use that sort of trick all the time, to save on special effects. Even movies with tons of special effects often do that, simply to save on budget and just keep things moving.
Personally, when something is overly flashy about showing me how amazing a job the animators/coders/designers/whoever did, it really starts to seem gratuitous. You know what I mean, where there is just a ton of excess emphasis on things that would normally be ordinary, but which they wanted to emphasize for technical reasons. You see this more in movies sometimes, and in a few AAA games I can think of, rather than anything else.
Or in a related example, it's like having a three-second animation that is really flashy and exciting, rather than having a 0.5 second animation that actually feels better for gameplay and doesn't make you want to rip your skin off after the 10,000th time you've seen it. The 2008 Prince of Persia game had a lot of that sort of thing, compared to the more economical and streamlined Sands of Time.
As with all things, there are infinite things we could do with this game. Question being: do we want to spend time making NPCs walk around and do stuff in a fancy scripted way? And do we expect you to sit there and watch that over and over again? Or do we put emphasis on things you and your character can do, instead, and keep to the gameplay? For me, clearly, it's the latter, but I don't think it's a cop-out.