Nothing so irritating
As moving the goal...which is what this does. Is there a business case for doing this? Yes, several. Is a clickbait title of hybrid is dead, or some other such stupidity immediately going to make me no take you seriously? Yes.
Hybrid arrays, flash arrays, yes they're expensive. But you're moving the problem. If I have a hundred hosts, then you can easily do the math and see where this is a bad decision. I'm using expensive Ram (not horribly expensive, but expensive enough), then I'm adding software licensing. I'm buying once for that array, I'm incurring the pernix cost, every SINGLE time I enable a host to do caching.
A few hosts? Sure, that's not a bad idea. Enterprise-wide? Don't be daft. You're looking 8-10k per host, all costs combined. By the time I hit that dozen mark, I'm thinking that 50k add-on to my array is looking a lot better. By the time I hit 20 hosts, that all flash array looks charming.