I kinda get what they are trying to do, but without knowing how many Discs and pads teams currently use at a race weekend it's hard to tell if this will cause much upset.
I'm also puzzled,
I can see restricting Discs could have a case, but why only one set of pads, surely heavy wear safety parts like that should not be restricted?
Is there something about high tech 'carbon-to-carbon' brakes in F1 that means the discs & pads have to be replaced together? Addendum:
having trawled the net a bit more it seems this one set per race may be FIA's way of nudging teams towards Carbon/Ceramic brakes, under a 'more road-relevant strategy', after being forced to pull the standard F1 brakes proposal.
Could also save a lot on cost too, if Discs can last 6 or 7 races as suggested by Brembo in this quote from Motorsport.com:-
"Carbon-ceramic brakes have most of the benefits of carbon-carbon discs but are more durable because the ceramics used in their production helps with thermal shock resistance.
The extra life also means there is less carbon dust released during their use, which has environmental benefits.
Asked about the possibility of brake discs lasting as many as seven grands prix, Almondo said: “It’s possible absolutely.
“I will also add that carbon ceramic does not emit [carbon] particles as much, so it would be more green. Yes it is a material that weighs more, but it could have the same performance – even in F1. The weight may be an issue that we face, but it’s something we could talk about.”
Extract from 'F1 could move to carbon-ceramic brakes in future' courtesy Jonathan Noble, motorsport.com, 16th June 2019.