Glen, I primarily use it as a guide to help new recordists understand how arranging works. It should be a big part of the producer's role, but all too often, I find myself acting as a "quasi-producer" for bands that just play everything all the time and wonder why their songs don't have enough emotional impact.
When I have them chart a song by a popular artist, it opens their eyes as to how a good arrangement works to enhance the dynamics of a song. It then makes it a lot easier to suggest that "maybe we shouldn't have all 12 guitar parts playing during the whole song".
Most of the time I just engineer, but if people ask my opinion, I'll point out various arrangement possibilities, but they hafta make the final call.
I'll point that out to them by saying something like, "Here's a possible problem, here are some possible solutions, but if you like it this way, tell me to 'shut the hell up', and it won't hurt my feelings one bit. They're your songs and you know them best. I'll continue to point out any possible problems I hear and suggest solutions, but it's always gotta be your call."
Most bands appreciate my involvement, but I hafta walk a fine line and really try to understand what they want and what they're doing, otherwise, I'm just trying to impose my personal tastes on their music. If I don't "get their music", then I keep my mouth shut. Most of the time, I do "get it".