ATM I am not getting a 2080 Ti for reasons you already know.
The way I look at it is if I had a 1080 Ti or Titan Xp as my main gaming card I would definitely be getting 1 or even 2 of the 2080 Ti cards for the reasons below.
1. It is going to be faster than anything in the Pascal lineup by at least 15% to 20%.
2. It is cheaper than a Titan Xp, if anyone can justify spending £1149 on a Titan then a FE 2080 Ti at £1099 can also be justified.
3. Ray Tracing is a nice little bonus if it works well but even if it does not the 2080 Ti is still a good upgrade over Pascal.
4. As you point out once the reviews are available you still have the option to cancel.
This is only my reasoning and PCs are my main hobby if my priorities were elsewhere I would find it difficult to justify the cost of these new cards as for most people there are other things more important in life.