I didn't realize these were available and perhaps others don't as well.
Lots of us are card carrying hammock mafia members
Also probably a bit cooler, since you are off the ground.
Yes, but workable with the right insulation underneath you:
I've slept comfortably in a hammock down to an outside temperature of -18C. (Although I typically go to ground if I expect that or colder)
Seems quite light, so with a tarp might still be lighter than many tents. Can set it up on ground if you run lines through the bug net to keep it off you. Need trees or perhaps stakes, though, to tie bug net cord to.
The rule is simple. Hammocks are comfortable for many people - however you can always sacrifice some of that comfort to go lighter - delete hammock, sleep under tarp - there, you are lighter. It is all about tradeoffs.
I hammock on most of my trips outside of winter. I don't hammock in deep winter up here, and I don't hammock if I'm going to be doing a lot of stuff basically way up in the alpine with no trees - I use a solo tent for those kinds of trips.