It's probably "useful", but it seems outrageously expensive for something that old. Like most lathes of that vintage it was probably a line shaft driven machine later converted to be driven by an electric motor. Speeds of those lathes are extremely low compared to todays machines.
I have a 1916 Seneca Falls Star machine that's similar in size and construction. The max speed is around 800 rpm. It can be run faster, but since it has a "total loss" lubrication system with sleeve bearings as opposed to roller or ball bearings it likely wouldn't last long. By comparison my 1960 Sheldon machine has a max speed of 2,000 rpm, has an encapsulated lubrication system, and uses roller bearings.
Again like most machines of the era threading is done by changing gears under the cover behind the headstock. Depending on the machine's capabilities there is usually between 10 and 18 gears. If they aren't all there it will be difficult to find replacements with the correct tooth count and pitch angle.
Wear is also something to consider on a machine that old. Most wear will be on the ways close to the headstock. It wouldn't be out of the realm of possibilities that the wear near the headstock could exceed .015". While it is manageable it will take some skill to make parts that transition the wear pattern.
With what little information you've given so far I would be hard pressed to offer half the asking price. That would only happen if the machine runs well, is in reasonable condition with all the change gears, and all the accessories shown in the picture.
There are certainly newer more capable machines on the market if you're intending to pay anywhere near the asking price.
