Didn't understand why this is the case. [1] If the sender pays from different addresses, should the system not make each into a seperate transaction? [2] What is the cut-off for deciding which sends are consolidated into one transaction?
Let me.
- 1. It will be less efficient in terms of transaction fee and if that's how transactions are made, the number of unconfirmed tx in the network will grow exponentially.
- 2. Your client (wallet) decides which input(s) (UTXO: visually, the addresses you see in the "input") to use.
The commonly used method is: choose the one with the closest balance to the amount being sent, if one isn't enough, the wallet will use two or more.
Some clients are choosing random UTXO(s) for privacy purposes.