I think XRB is now exchanged on 3-4 sites and they all only have various levels of support.
I think the DAGs (XRB, Byteball, IOTA and likely many more I am unaware of) have the potential to be very useful for microtransactions.
Due to the one-use addresses your entire funds are stuck, because you can't resend from that address, so you can only wait, reattach and 'promote'. Promote means create a 0-value txn confirming your txn that ends up being more likely to confirmed itself. Nice in theory.