Seems I'm writing about MHL as a special feature on just about every home entertainment hitting the market, and even a home theater projector or two.
So, here goes. Again! The Epson supports MHL on it's HDMI 1 port. MHL is just a smarter HDMI port, that accepts the MHL ("Mobile High definition...). It allows you to plug in a range of smart devices, even including some Android phones and tablets. The best example though of what MHL is about, that I frequently use, is to talk about the Roku stick I own.
My MHL Roku stick plugs into the Epson Home Cinema 3500. It is a Wifi device that brings me content over the internet via my local Wifi. It is an alternative to my satellite box, blu-ray player, etc. It's closer to Apple TV. I can stream movies from Netflix and other services through my Roku stick, there's a huge wealth of channels - of content, out there, some free, some with fees.
You can almost think of using Roku stick or similar, as similar to cutting the cord with phone service, no more "old school" land line. Here with MHL, and devices like my Roku stick I can cut the cord - no satellite or cable, no Blu-ray. Truth is, I wouldn't even think about abandoning Blu-ray, the picture quality is so much better than streaming, or HDTV.)
BTW not all content is accessible via Roku and similar products (Google has Google Play, even Amazon has one. for example to get a live NFL broadcast, that might come from a different channel, perhaps via an NFL channel. But, you can't count on access to everything you get with 600 channel satellite.
That said, MHL simply expands your source options with the HC3500.
One thing. For most things MHL, you get audio as well, and also some command and control. As a result, a projector pretty much needs to have its own audio built in. Well, Audio is next!