A few cents worth, based on this year's chases.
Years ago, before I had the wherewithal ($ and a reliable car for cross-country driving) I was a spotter for Douglas County (Omaha) REACT. I did it for one year, and while I understood the difference between chasing and spotting, there were a lot of factors that caused me to quit after one season. Political power plays between the graybeards and the 'freshman' class--not over the storms themselves but over radio protocol (you couldn't mention the word 'tornado' over the air, even in the middle of a warning, for one example).
That said, my chasing has been for my slavish self-interest, not for any civic duty or scientific advance. Implied in that statement is a desire, in return, to not be a burden on society by needing EMS to pull me out of a ditch or cut me out of my car, dead or alive.
This year, mostly due to tunnel vision but also due to storm-scale surprise, I've driven through circulations at least twice. June 05 just south of Johnson, NE, I almost did but I thought better or else I decided I was sick of being stupid. Once I noticed the wind shift within a space of ten feet I backed out.
Immediately, a spotter indicated a tornado and there was damage in Johnson. Point is, I knew I was near a radar-indicated but I couldn't see a funnel, tornado, damage or anything. Some spotter did, it must have been at close range, with all the rain and the storm speed this spotter must have had a view for only a second and it must have been close. Also, they probably were north of a northbound tornado.
I would not put myself in a stationary position such as that by choice, but someone had to. I knew what my reaction would be once I ran into the windshift and acted upon it, but given the visibility the spotter didn't have that luxury.
I know that not all spotter networks aren't alike, but across the board I have a renewed appreciation of their dedication.