A hot wallet holds keys on a connected device: a browser extension, a phone, a server. Connectivity is the point, instant signing for everyday flow, and connectivity is the risk, anything the device can reach can reach the keys.
Hot wallets are for velocity, not value: payment float, trading balances, the gas tank. The discipline is replenishment from cold storage on a schedule, so a compromise costs a day's float instead of the treasury.
Checkout wallets and swap wallets are hot by nature; U.CASH's non-custodial design keeps even those keys yours, so the exposure decision, hot float size, cold sweep cadence, stays with the holder.
Every term behind the rails, the assets, and the settlement.