Are you sure it isn't already installed? I thought it was standard with 11x (for standalone use). Do an swlist -l fileset|grep Ignite to see if you have it.
If you don't, the software description says it doesn't require a reboot.
It is a relatively benign piece of software. Depending on how nervous your production folks are about having software installed, I see no reason why you shouldn't install it. In the end, it's for their own good (so you can plan for disaster recovery, for example).