The problem is the processing time for bitcoin is too slow and unreliable, it's not like ordering online where you can wait for the bitcoin transaction to be processed prior to shipping the product.
The speed time is really what's delaying the wide adoption of bitcoin but this would be pretty awesome if lyft/uber did this.
Yes,the huge time taken for confirmation would be a big issue.But if it gets accepted,definitely it would help bring bitcoin into the mainstream of daily usage.It would make it more popular and would make critics mouth shut who just blame that bitcoin could not be used as a currency.