I believe inulin is actually considered a pre-biotic, which would be a good thing to add to your pro-biotic intake. Also, it's a soluble fiber, which as you know, can aid in the slower absorption of foods. I had recently bought fiber sure, which is 100% inulin. It mixes very well and is tasteless compared to psyllium husk.
The only thing different I notice is the psyllium husk will keep me fuller longer, so it's probably a more effective source of soluble fiber.
I think I read somewhere that inulin can help with Calcium uptake, but I'd have to look that up as I cannot remember the source.