Yes, .44 mag is primarily a pistol round. That's exactly why this rifle is attractive to me - I already have a Ruger Super Red Hawk in .44 mag, and reload for that, so ammo is less of a problem. Plus, the heavy 240 gr typical bullet should make a very good hard-hitting rifle round. I'll only expect it to be useful for under 100 yds, probably more typically under 50 yds. Sorta like a super-long-barreled pistol!
I'm not yet a student of Winchester history, but Wikipedia says that the Win 94 started life as a blackpowder rifle; "It was designed by John Browning in 1894 and originally chambered to fire two metallic black powder cartridges, the .32-40 Winchester and .38-55 Winchester. It was the first rifle to chamber the smokeless powder round, the .30 WCF (Winchester Center Fire, in time becoming known as the .30-30)." The .38-55 cartridge is similar-looking to the .44 mag, rimmed straight, but the .44 mag is shorter and fatter. It has been chambered for up to the .450 Marlin. Over 7 million have been sold, but all production ceased in 2006.