Many implementation details can be hidden by the user interface. A wallet might keeps a set of addresses with small balances and ones with larger balances. I d

Many implementation details can be hidden by the user interface. A wallet might keeps a set of addresses with small balances and ones with larger balances. I don't think book flights and hotel reservations would require you to wait until previous transactions clear, these kinds of businesses always have the option to cancel your booking if they notice a double-spend on your side. Edit: in general, businesses that receive your payments days in advance of delivering the product, Bitcoin is a better alternative than Credit Cards which can have chargebacks weeks after or charge a high fee