That being said, (a) the tech does seem to remove a lot of error factors from backlighting, and (b) TRILUMINOS is only available on the higher end TVs, so one way or another there is going to be some kind of quality difference versus a random W700 or whatnot. You're getting a higher grade panel, a better backlight, and whatever extra tech that comes along for the ride (like the wedge speakers, better smart TV CPUs, etc.) So it's not smoke and mirrors.
That's not all.
VA Panels have been historically dimmer than IPS, which is why it took so long for them to take off the ground. These things get to be shown on stores all the time and picked by people who are not very in the know, so they go for things they can pick up, like peak brightness being higher ("that television is dimmer! nahhhh" - usually) or colors being more saturated (ugh). On a store VA panels can suffer to a certain extent like plasmas did, is what I'm saying, while abundance of light shields the fact IPS blacks are... well, shit.
Sony triluminos VA panels are pretty much the brightest VA panels I've ever seen, and that's an advantage for stuff like strobing/impulse and... daylight viewing. (nobody is his right mind wants to see TV under those situations, but it can come in handy), and yet they're also some of the best dimmable LCD's out there, so it's very good.
As for the wider color gamut, for me it's the closest to Plasma/OLED on the LCD field, and that's a pretty big advantage over it's competition in my book, but I completely understand where you're coming from with it.
The cost in projectors isn't the projector itself, it's the cost of building the home theater room in your house to accommodate it and the bulb replacements. The unit itself is cheap but you'll be paying a lot more upfront to install it in a home and then you have constant consumables replacement during it's lifetime. Also if you move it's awfully inconvenient to rip everything out and take it with you. A TV you just pick it up and bring it to your new house.
I was thinking something short throw for sure.
The W1080ST has under 33ms of lag (I've heard 24ms, iirc), and it's DLP (so blur is not an issue and doesn't need motion compensation, unlike with projectors based on LCD tech), it's virtually better than most TV's out there for this task... and cheaper.
There's not really a special installation involved. This said, 55" means having the thing like 3 feet from the wall. And might I stress I'm not a projector fan at all, if I ever buy one it's because I can accomodate it and it somehow trumps the TV I would have otherwise or something.