I think that making sims actually look, feel and smell like a real aeroplane helps the realism and improves the quality of training. Sure, you can build down to the minimum spec - but it shows.
Our Seneca sims are actual Seneca cockpits, our Hawker 800 sim is a 100% accurate copy using aircraft instruments, switches etc. These facts bring positive comments from people who have seen and used lesser (certified) machinery which is at the bottom end of the realism scale.