These are old school letter prefix names developed back in the wild west days, before people understood what direction the internet would take and before anyone knew what was going to be optimal in a name platform. They would hyphenate the letterprefix-keyword and use that as their primary development platform, even if the unhyphenated variant was available.
I kind of view these as the domain equivalent of outdated gear. Uber-sophisticated interweb long-timers can instantly identify these names for what they are and usually view them as being kinda 'retro-cool' (like an old, beat-up pawnshop guitar is to a musician), but for full scale development geared towards separating John Q Public from his money, things have progressed in a different direction.
Still, I agree there is some value there (especially with this one) but not nearly as much as if you owned the unhyphenated version, even though the pure version may be newer (I don't know- I haven't checked). I think it was John Ruskin who had a cool quote about things whose sole virtue was their age... I'll see if I can't find it.