I haven't heard this yet but I think the idea is good.
If more people will become aware of Bitcoin and will convert their cash to coins. It's a perfect opportunity that could raise the value of coins. I always imagine a world without cash, it's contactless. I envy how they do it in China using Ali Pay and Wechat Pay.
Although I agree with what you've said about the processing time for the transfer. I hope they would find ways to improve it.