[..] wait a few minutes to accumulate a bunch, ask the user if they are willing to wait to pay a lower fee.
From a business point of view, I do not really understand why to spend time and effort on this if the transaction costs are covered by clients in one way or another. But such a decision would be very clever from a marketing point of view, since by spending a little money on updating and implementing this feature, you subconsciously convey to customers the idea that transaction costs on your platform are lower than on competitors' platforms,
(even if the client never uses this function + you offer what your competitors do not offer.).It should be quite simple to implement:
When your site has withdrawals, and, for example a user wants to withdraw 1 BTC, he sees a couple of options on the screen:
1. Withdraw 1 BTC fast, usually 10 to 20 minutes, withdrawal fee is 0.02 BTC
2. Withdraw 1 BTC with batching, can take up to an hour, withdrawal fee is 0.001 BTC
That's just an example. At least you give the user a choice. Some people don't mind and can wait the extra hour or two, and pay less.
I think that's good for business. I ran a bitcoin "gaming" website before.