It does serve a legitimate purpose - just not on every website. Here at work it's used in combination with JS rendering to provide interactive, animated, and windowed reporting dashboards for clients which can be viewed on almost any modern tablet, smartphone, or browser without needing a plugin or application install. Loads in seconds, and they can play with the data.
... and other than MANIFEST, (one of maybe two or three things that serve a legitimate purpose alongside RUBY support) what does it actually use from HTML 5 that couldn't have been done with 4 Strict?
Though yes, crapplets do operate on different rules from websites; though if that's ACTUALLY a website, it sounds like it probably pissed away accessibility for goofy animooted nonsense to make up for a lack of actual content; I may be mistaken, but as a web developer your description ALONE throws off alarms in my head.
Generally speaking, 99%+ of the garbage people vomit up in HTML 5 is just as broken, backwards, and the antithesis of why HTML even exists as the nonsense people vomited up with HTML 3.2 or 4 Tranny. Between the allegedly semantic new tags (section, article, nav) that are redundant to numbered headings and horizontal rules, that are so presentational you might as well go back to using FONT and CENTER (aside), idiotic re-introduction of redundancies (Audio, Video, Embed) that HTML 4 Strict was trying to get rid of (with OBJECT), elements that are scripting only and as such shouldn't even HAVE tags (CANVAS, PROGRESS) and new structural rules that reek of the W3C shrugging their shoulders and going "Oh well" -- it seems carefully crafted to undo all the progress of the past decade and a half. It sure as shine-ola has jack to do with writing cleaner, simpler, clearer code, leveraging proper semantics or logical document structure, of practicing separation of presentation from content.
No wonder most of the halfwits slurping it up off the floor embrace other idiotic bull like bootstrap and jquery, pissing all over their websites with hundreds of K or even megabytes worth of HTML, CSS and Scripting to deliver single digit K of plaintext and a half dozen content images; Then go to web development forums asking "why is my site so slow" or "why are users complaining about it"
There's a reason I say most web developers have failed to extract their craniums from 1997's rectum, and now HTML 5 is set to make certain it stays wedged there permanently.
Now I'm not saying that what your 'workplace' is doing falls into that category; but if it's ACTUALLY using HTML 5... dimes to dollars it does.
Unless by "HTML 5" you were referring to all the things that have absolutely NOTHING to do with HTML; See the new ECMAScript support and CSS3 -- which can be used JUST FINE with any of the recommendation doctypes (HTML 4.01 Strict, XHTML 1.0 Strict) because *NEWS FLASH* -- they are NOT HTML 5; no matter how many drooling morons in the media not qualified to open their traps on technical subjects call them that.
Which is why HTML 5 is quickly ceasing to be a specification and instead becoming a sick buzzword ignorant fools abuse like "Web 2.0"
That's actually the real laugh of it, all the really 'cool' stuff people call HTML 5... Isn't... At all... and the handful that is (AUDIO and VIDEO), should have been implemented on OBJECT so we don't have vendor lock-in shoved down our throats and stay true to the intent of 4 STRICT.... the REAL laugh being they then sold it to the masses as FIGHTING vendor lock-in. (Flash) when it's the exact opposite. Gee, do I smell Apple's sour grapes over losing the last media format war in the mix there?
Again, sorry... pet peeve. Painful to watch people repeat the same mistakes over and over again...
So the little 386 is upgraded all the way to 32 MB of Ram and 256k of cache. Of course I had to completely reinstall Windows 3.11 for Work Groups, because it just wouldn't start with the new memory. Grrr. 
