There are significant differences between caramel and crystal malts, even though the terms are used interchangeably in the US. Generally, caramel malts are produced in a kiln and crystal in a roasting drum, resulting in different amounts of carmelized/crystalized starch in the grain. Then there is the practice of blending caramel malts with very lightly kilned malts to hit color and flavor targets, as is often the case in Germany.
What this all comes down to is that using 5% crystal 60L malt with full crystalization will taste far sweeter than a similar caramel 60L product made in a kiln, where only half of the starch is caramelized (the remaining is essentially toasted). Similarly, using 10% carahell malt in a bockbier may sound insane, but in reality only 3-4% of that total could be crystalized starch. For a US example, a beer like Celebration Ale uses 10% caramel malt and while sweet, it is not cloyingly so, at least when fresh. Brew that same recipe with a UK crystal malt and it is undrinkable. My last point is that you can add toasty-biscuit complexity to beer using caramel malts that you generally don't get when using crystal malts; this is useful when brewing with neutral US/Canadian pale malts.