Yes. I went through this with a car that had been Ziebarted. There was in fact a reason to coat stuff in the engine bay, but you're not going to like it. It was to give the customer a sense that they were getting a good deal. The customer can't see inside the cavities where the stuff did the most good or even much of the underside of the car, so people sort of left the shop feeling like they might have gotten ripped off. However the customer CAN see the engine bay, so the applicator was instructed to coat a few obvious areas under hood to make the customer feel more confident that they actually got something for their money.
But everyone expects to look under your hood at a car show today (at least here in the U.S. they do). So I once undertook to remove that shit from an otherwise spectacular car. I knew I'd have to repaint the engine bay, but that was the least of my worries because I had the engine out for a 7mgte swap anyway. I tried every suggestion that I could find on the web, but the final solution was just to scrape off as much as possible with razor blades and flat xacto blades and then get the last little bits with acetone-soaked steel wool because it seemed the least poisonous stuff that would dissolve it. That was by several orders of magnitude the most tedious restoration task I've ever done and I've done some really loathsome tasks. I've resolved that I'm not doing that again.
