Well, the benefit is quite obvious - there will be no additional inflation.
Look at it this way.
Hive is worth $10 usd - as author you earn 100 hbd.
At that time, you can buy 10 Hive with 100HBD - via conversion. If you decide to wait a bit longer and the price of hive sharply falls down to let's say $1 usd, now with the same amount of hbd you can convert it to 100 Hive tokens - 1000% newly tokens are being minted, thus increasing the inflation above predetermined rate.
HBD is good tool during uptrends and has been designed on a premise that crypto in general will rise in price - long term.
Good explanation - thank you - he should have included a link to the proposal here.