This should have been throughly thought before hand when the original staking was at 3% and it was already trading on c-cex. The question is why NOW?
NOW is always a good time to do the right thing. Staking was never 3%.
The original PSB and the PoSP hard fork that followed have 5% as the official inflation rate, but, because of how wallets are staking now, the actual inflation is 6%-6.5%.
Also, we found out that C-Cex is one of the only exchanges that actually stakes with depositor's coin; this is something we didn't know.
Making PSB a 3% coin will make it more rare and help price. It's just one aspect of the coin, but an important one.