The main difference between evaporated milk and condensed milk is the sugar content. Evaporated milk has almost no sugar, while condensed milk is packed with it. This means that if you use condensed milk in a recipe, you'll end up with a much sweeter final product.
But, let's be real, who doesn't love a little extra sweetness in their life? It's like the old joke, why did the condensed milk go to therapy? Because it was feeling a little sweet and overwhelmed! Okay, maybe that joke was a bit of a stretch, but you get the idea.
In all seriousness, using condensed milk instead of evaporated milk can be a bit tricky. It's like trying to substitute a Mercedes for a Toyota - they might look similar, but they're not exactly the same. You'll need to adjust the amount of sugar in the recipe, and possibly the amount of liquid, to get the right balance of flavors.