Aesthetic details.
I was just explaining this to my girlfriend, and it's why I love the Tower so much - even though I too, am disappointed with it being 'just a bathroom'.
Every era of Imagineering architectural design, is obvious, if you pay attention. In other words, there is noticeable contrast between what was built in the 70's, 80's, and 90's. Techniques and technologies developed, and of course, with our technology today, and everything we've learned, today's designing... tops every era all.
I am a little OCD, and a big believer in feng shui - I believe it's a law, not a theory - and adding a section built with modern-day architectural and designing techniques among that of a - ridiculously corny - 70's section... 'feels' good to me, instead of it all being crammed and compiled up into the 20,000 Leagues plot.