I would test some of the fabric by washing first as it would depend on the quality and type of block out used.
I made a picnic rug using block out as a backing. It has held up to many many washes very well. Then I washed my dd curtain on a delicate cycle and the block out backing peeled away. they had only been up for 12 months on a protected side of the house.
Yes, you should be able to use it, but make sure you use your special roller foot (it glides over the rubbery fabric easier) and a good size 14 or 16 needle. If you use the suede type fabric I think that is more a 'dim' out fabric. Love Chris
Don't see any reason why you couldn't or shouldn't. Give it try. Hugs. Nan W