Can transactions be seeded up to save customers time or any other way to use bitcoin at local stores.
Slow.
If you want to be sure of the transaction - and a proper store will always make sure it doesn't lose money - you need at least one confirmation.
On good days a confirmation takes some 20 minutes. On bad days, especially with the current spam attacks / clutter on the network, you need high fees just to make sure your transaction goes through within hours. The unlucky ones wait for days, just check the threads around.
So it's slow. And unless something is done, it will become even slower and more expensive.