It was for an 80286 clone that had a 10MB HDD. His rational for buying this card was "I can make a big RAM drive out of it and run everything from memory"
I can't recall the price of the thing, but I want to say it ran in the thousands. Couldn't run most games on it because of copy protection so we never got to take advantage of it. In fact, I don't think the extra memory was usable at all in most software -- I recall we couldn't run a game on his machine due to having 512MB of onboard memory, but it had no issue in my ancient 8088 with 640K installed (in bizarre CGA colors).