Yeah, I wouldn't see any issue with it, it would be similar to storing the car on axle stands. As mentioned, more solid blocks would be good and you would definitely want to have proper jack-point adapters, something like
https://www.ecstuning.com/b-ecs-part...pter/ecs10721/. I use rubber pad adapters normally with the rubber blocks and they're fine for several days but do deform a fair bit.
I have had another vehicle up on the QuickJack that shifted on the rubber blocks which was rather scary (nobody was under it, it was for a summer tire change over) so now I'm really cautious about making sure the frames are on very level/solid ground and the blocks are stable before lifting the cars entirely up in the air.
The QuickJacks are very stable but the car can only be as stable as the blocks & mounting points they're on, so keep those solid and you shouldn't have any issues.