As has been stated previously, in a casual game no one gives a monkey's if you use whatever you've got, but in a tournament setting it's not unreasonable to require the correct components. A game ship consists of four components. Why is it so hard to ask for them to be the right components?
It may be designed to generate profits, but would you rather have FFG make silly rules that potentially cripple them financially? And force possible abandonment of product lines? I think FFG have been really accommodating by including extra dials in the Most Wanted pack. They could've just made a repack of the HWK and Firespray with the S&V cards and forced everyone to buy another expansion, but they've figured that gamers would rather use existing models and have catered for that nicely.
I don't think it's a huge price to pay to get the right components, and if I've gone to the effort to do it, I'd expect my opponent to do the same. I've seen too many games over the years where proxy models or components have really made the games suffer.