The point is that the hex looks the same as the decimal. The actual address doesn't matter. They’re not doing for decimal 254. They’re going for “the last part of the address is familiar and typed the same on a keyboard”.
Sure. I was just pointing out that if you really wanted to use 254, you could use fd00:ec2::fe and write it as fd00:ec2::0.0.0.254 -- though mainly because I wanted people to know that doing so was possible, not because it was in any way a good idea in this case.
(At least, I was trying to point that out, but re-reading my post it's obvious that I didn't do a very good job.)
