I designed a system like that for the place I currently work. I'm positive the person who follows me in my position will curse me as the Devil. However, before I set up that system, documents were created with weekly batch merges that took one person two days to complete. Now a batch can be run in about 2 hours. I'm a huge Linux nerd, but it was easier to get something working with the existing infrastructure using COM than design something entirely new with PDFs and typesetting software, or whatever. Working in Windows drains my morale, sure, but making everyone else at my company that much more effective is a huge morale boost for myself, and it boosts the morale of everyone else here too. It also allows us to serve our constituents better, which is rewarding as well.

That being said, I wish I never had to program a mail merge in the COM ever again.