I have been playing around with a private Monero test network and I noticed that the transactions always have two or more inputs. When I inspected the true inputs of a transaction, I observed that one input has more value than the total transaction value. So it is not the case that Monero is combining multiple inputs to send a large amount of XMR.
Why does Monero create two or more inputs for transactions?
This is done to try and make more transactions look the same. An attempt is made to make the transactions a 2/2 (2 input, 2 output transaction). Therefore, even if one of your inputs has enough to fund the output(s), the wallet will attempt to add another input as well.
// for rct, since we don't see the amounts, we will try to make all transactions // look the same, with 1 or 2 inputs, and 2 outputs. One input is preferable, as // this prevents linking to another by provenance analysis, but two is ok if we // try to pick outputs not from the same block. We will get two outputs, one for // the destination, and one for change.
// while: // - we have something to send // - or we need to gather more fee // - or we have just one input in that tx, which is rct (to try and make all/most rct txes 2/2)
So it is not the case that Monero is combining multiple inputs to send a large amount of XMR.
This is a slightly different question/observation and is incorrect. Monero absolutely uses multiple inputs to fund a large output. For example, if you own three outputs with values 10, 50 and 100 XMR and want to spend 130 XMR, the wallet will create a transaction with two inputs (your owned outputs that have 100 and 50), and two new outputs (with 130 and 20). The 2nd output is your change.