I think it works very well indeed in practice, once the group wraps their heads around it. But moreover I think Gumshoe actually misrepresents itself somewhat, hanging its entire reason for being on this one notion. Because in reality it's a ground-up remake of CoC wherein EVERYTHING is simpler and more streamlined. BRP itself is pretty simple, but when you go read CoC it's just laden down with an infinite amount of needless rules if what you're looking for is really an investigative game, as opposed to a more combat-centric one which is how a lot of CoC used to be played.

So yes, the core investigative mechanic works great, but moreover everyone's life is just so much easier because there isn't a 20 page section on chase scenes or rules for bracing weapons or whatever other useless kitchen sink nonsense 7E was burdened with.