On the contrary, in my experience it's much more important to "play" with a concept and see it working. Too many engineers think they're going to architect a perfect solution without ever getting code on the page.
A slapdash prototype is worth the weight of 100 tests and arch diagrams.
Note: I'm not saying the latter is not important. My comment is, it's ok (and encouraged) to do potentially throwaway work to understand the domain better.
