Honestly, your website is probably the best implementation of a SPA website with multiple pages I have ever seen I can recollect. It still has quirks though. I just don't see why you would want to make a website like this a SPA.
Does that help a little? I wrote this quick, off the top of my head. I can try and provide more details maybe in an email or some other communication means too.
Why SPA? Well, a good question indeed. Actually, we're cross-compiling the same code for the webapp onto iOS and Android targets with build flags, where we're leveraging more platform features (i.e. geolocate cinemas).
Also, it lets us make the experience itself much more snappy once you're on the page, as there's just content to be re-loaded. You can switch tabs, we can remember scroll positions, stuff like this.
Stay tuned though for our completely rewritten release based on very recent technology, I'm hopeful this will change your perception about SPAs on large sites coming in March!
Nothing can possibli go wrong