I started doing is as part of @streetstyle's initiative on the earlier iteration of this blockchain. Probably about three years ago. It was/is an incentive for to get folk to HODL and also to pay attention to their accounts and how they can grow - if one pays attention. My participation helped me - I received delegations and I learned more about how the blockchain works.
In terms of powering up once a month, a key benefit is from putting both Hive and HBD in savings and earning 20% APR. That's a no brainer. Making it work before adding it to your HP.
Trust that helps.
Thank you for your reply! Now I understand.