The use of PDF's is usually for it's immutability. Not all PDF's are created equal. Some are harder to change than others - but there are many tools and options

The use of PDF's is usually for it's immutability. Not all PDF's are created equal. Some are harder to change than others - but there are many tools and options to change them, if you need to. However, it is possible to turn HTML5 into statement-of-record documents (Not PDF's),and make them immutable, encrypted and authenticated. A HTML5 document can have the features we need from PDF (immutability, encryption, authentication, pixel perfect print, etc.) while still allowing the resulting document to be interactive and responsive (work well mobile & web) in nature. Effectively the best of both worlds.