This is hardly beyond standard practice in the industry. The SLS is going to orbital flight with no flight testing. Heck the Falcon Heavy launched a car past Mars' orbit on it's first flight. I think SpaceX's main goal was to refine their manufacturing process and make sure they can achieve a certain level of consistency in building these things. The fact that they installed all these Raptors before even doing a pressure test tells you they are far more confident in their processes than they were even 6 months ago.