That's a good point
compressor stall . It's a natural reaction to want to keep out of the red band. I guess most pilots just overreact a bit when they see the speed in the red and increasing. Airbus Safety first published the VD for each model, and as you you stated, the margins are generous. 381/.89 for the A320 series.
https://safetyfirst.airbus.com/contr...eed-in-cruise/