So I need two wallets? One that I keep with a <bitcoin-bank> for small purchases that need to clear quickly and one that I keep for larger purchases. That doesn't sound practical.
Also, if I understood patio11s first post correctly, that large-purchase wallet would still need an hour after each purchase to clear properly [1]. Now, I don't run around and buy a couple of cars one after the other from different provides but it quite often happens that I need to book flights, hotel accommodations and rental cars for a business trip and I can't wait an hour after each step to go forward to the next one. More wallets here? Am I missing something?
[1] The ideal case seems to be to wait until a transaction is in the blockchain before sending the next one from the same wallet, but that could in theory take even longer.
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
You can avoid the issue by not sending a large quantity of BTC all at once to a single address. For example, after buying from Coinbase, fan out your BTC in small increments to many addresses.
In Electrum, you can right-click on a receiving address with 0.1 coins in it, and choose to spend coins only from that address ("Send from").
Same principle as not carrying around a wallet full of $1000 bills.
Also, if I understood patio11s first post correctly, that large-purchase wallet would still need an hour after each purchase to clear properly [1]. Now, I don't run around and buy a couple of cars one after the other from different provides but it quite often happens that I need to book flights, hotel accommodations and rental cars for a business trip and I can't wait an hour after each step to go forward to the next one. More wallets here? Am I missing something?
[1] The ideal case seems to be to wait until a transaction is in the blockchain before sending the next one from the same wallet, but that could in theory take even longer.