If this change is applied, the collators that are active will be determined about every 2 hours (600 blocks * 12 sec/block = 2 hours). In addition, reward calculation and payouts will also be done every 2 hours. Those two processes are very intense operations that the chain has to execute currently every 4 minutes, so making this change will unlock many resources for transactions. Other side effects are that decreasing the bonds or leaving the candidate set will increase to 4 hours.
Changing the blocks per round to higher value is also mandatory to increase the active collator set size.
We decided to go with 2 hours based on the example of Moonriver, a parachain on Kusama whose organization created the parachain-staking pallet that is handling the blocksPerRound value.
Thanks for your participation!