RPGMemes

Yeah, people would understand it, but would look at you funny.
Partially, because they're just not used to it. "Hochseil" and "seiltanzen" are composite words, but are also just used commonly, so they have made it into the dictionary as separate entries. Meanwhile, "hochseiltanzen" is merely a neologism at this point.
But it does also just sound like you're really shoehorning in that you're specifically walking on a high wire. Like you're just bragging about it.

What's also kind of funny, is that we have nominalization in German as well, so where a verb (or other word) is used as a noun, and using "das Hochseiltanzen" as a noun does not sound out of place to me. In fact, when I throw "hochseiltanzen" into a search engine, I get four results, all of which use it as a noun and like it's a completely normal word that does not need explaining.