financial incentive is coming from the 2% inflation. If 50% of Koin is burned this equates to a 4% APR. I expect it to be rather between 5-6% since not 50% will always be burned.
I suppose the idea is to have as many burn pools and individual nodes which would mitigate several bad actors with large "stake" (i.e. Koin which they can burn)
see Justinw