You have the same reasons as I did for switching to a chromebook for most of my computer needs. I'm very happy with my chromebook. I don't have answers to all your questions, but I have some opinions and notes on what worked for me.
I have both a tablet, (nexus 7 2013), and a chromebook, (Acer C710-2815), and for the purposes of this conversation, a Samsung Galaxy S4 phone.
I use them completely differently. The tablet and the phone overlap the most, with the tablet serving more time as e-reader and video streamer. The phone can do everything the tablet can, but smaller, obviously, but I've come so dependent on the tablet, when I broke my 2012 nexus 7, I went out and got a replacement after trying to justify not needing it.
I do not think the tablet serves as a desktop or notebook replacement, even with a bluetooth keyboard and a cloud printer which all 3 devices can print to.
The chromebook is leaps and bounds better for document creation, email and even texting. (There are apps and extensions that allow you to text over a network to your phone.) With a wireless mouse and cloud storage, I could survive without my desktop, though I would have to give up some programs that require hard disk installation.
Bottom line, I would have a phone first, of course, and given no other personal computer at all, I would have the chromebook. The tablet is a luxury, albeit a very important one, like a microwave in your kitchen. You can live without it, but why?
This is what I found important to me when I was shopping around:
*SSD drive for durability, as you noted. The acer can be upgraded to a larger ssd, but it might void your warranty, so I haven't done it yet, and after a bit of time with the chromebook, I don't foresee a need to upgrade yet, but I love the ability to do so.
*4 gigs ram - I've heard 2 things: 2 gigs is not enough for smooth video watching and 2) the acer can be upgraded to 2x 8 gig ddr3. I haven't tried it, (you'll void your warranty, I think, you have to take off a little sticker that says so), but again, I love to tinker, so I will probably do so at some time.
*6-7 hour battery, it does not add any bulk that bothers me, and I don't know how the 4 hour battery fits, as there are no batteries in the demo units, but the extra bulk of the 6 hour batter serves as a nice tilt feature for the keyboard. Because the chromebook sleeps and wakes so quickly, I easily use the unit all day, off and on without plugging it in until night.
Anyway, this is what worked for me, I'm happy with the chromebook and I could imagine having it be my only computer as long as you have a cloud printer, though at the very worst, you could email documents to your self and print them out when you're at a wired printer.