This sub-VCM represents playing the role of a block validator in NEAR and all the benefits it entails. Once a user accrues a stake in excess of a dynamic threshold, which is determined as the greater of the values of 25500 NEAR and the value of the 300th validator proposal, he becomes enters the set of chunk validators and becomes eligible to enter the set of block validators, which is composed of the top 100 validators by stake, at which point he can participate in securing the consensus by producing chunks and producing and validating blocks. Rewards are derived from emissions with a dynamic target APR based on the stake rate of NEAR, with the details being given at https://www.near.org/blog/near-protocol-economics.
Validators with uptime of less than 90% are bereft of rewards.