It's the pre-coded rate of inflation in Rise, the block rewards are the incentive to have multiple delegates securing the network.
Over the next 5 years Rise has the following rate of inflation.
Year 1: 15 RISE per block, 115,768,000 Total coins with 15.77% annual inflation rate
Year 2: 12 RISE per block, 128,382,400 Total coins with 10.90% annual inflation rate
Year 3: 9 RISE per block, 137,843,200 Total coins with 7.37% annual inflation rate
Year 4: 6 RISE per block, 144,150,400 Total coins with 4.58% annual inflation rate
Year 5: 3 RISE per block, 147,304,000 Total coins with 2.19% annual inflation rate
Year 6+: 0 Rise per block and therefore 0% inflation.
At the end of the the fith year there is 0 block reward and transaction fees alone will sustain the network.
Rewards should only be enabled once the non-genesis delegates start to forge just like it's with LISK it's not fair to the community since you already reserved dev fund, got the ICO funds and now rewards from all the genesis delegates.
P.S. I'm not bitching just saying as an investor

Agreed that the sooner we get the rewards going to public delegates the better. They were going to the public but we had to switch that back because of the forking issues.
Right now the rewards being generated by the genesis delegates will be put to use for the benefit of Rise by the way of bountys and promotional work, we could even create a public Rise pool where we place the funds (rise generated) and allow the community to decide how it gets spent. For example another signature bounty or twitter promotion and we vote to allocate 600,000 Rise for those purposes.