The cushion was there before HF20. Printing of SBD had stopped well before HF20. The cushion stops the printing of SBD well before the haircut takes place. The change was put into place to continue printing SBD right up to the haircut. Now we are in haircut territory. When haircut takes place, you no longer get $1.00 worth of STEEM for each SBD. Thus the bottom price of the SBD peg is compromised.
The conversion was once a thing built into the Steem wallet via the Steemit front end. Back when SBD prices were sky high, that option was removed to help prevent people from converting and only getting a dollar worth of STEEM for each SBD. I agree that this was the right thing. When SBD fell to a dollar, I argued that the option should be reinstated. This is where 99% of STEEM users actually use the wallet. Witnesses knew this and decided to keep the option out of the Steemit front end where most use the wallet. People found it more convenient to use the market which doesn't convert the SBD. This was all part of the plan to prevent conversions and over-inflate the SBD supply to manipulate SBD price. Changing the print rate of SBD was just another tool to over-inflate SBD supply. It was a gamble that backfired.
If you want a stablecoin, then create a stablecoin. SBD is not as stalecoin. It is a tool to grow the STEEM economy. You should research how governments use debt instruments to help grow their economies. You will find shocking similarities. It is genius really to have a debt instrument built right in our STEEM economy. The dumb thing was to try to manipulate it to artificially control price.