present value of the expected loss and expected loss

Can someone help me understand the concept of pv of expected loss better? and why does credit loss play a part in this? shouldnt this just be a simple discount of expected loss?

PV of expected loss is like a spread that you see in bonds, except it is the spread in the value/price of a risky bond vs a risk free bond.

(Usually we see spreads as difference in yields not prices)