The Po-2 is the cheapest flying contraption of ww2, seeing great demand in it's service due to a huge array of positive aspects, some of which are unique to the Po-2. Most of these are not in the game for balance purposes.
The Po-2 was so cheap it actually had a wooden hull. In fact, pretty much only the engine was metallic, so the Po-2 would only show on pretty powerful radars. In game, the Po-2 costs the same amount as any other scout - 1000 command. To compensate, it's speed was raised to match the rest, making it indistinguashible in terms or performance. The draw back of this means that flak weapons can actually aim and hit the aircraft, while the real world version moved too slow (flaks have settings to lead their shots to compensete for projectile travel time and most flaks had no preset leads that allowed to compensete for the Po-2, making every flak weapon overshoot by about 50% distance). Due to the mechanics of the game, the rare ability of the Po-2 to land on almost any strip of land (paved, dirt, grass) is as negligable as it's ability to hide from fighters by making circles around a tree.
The in-game Po-2 is used only for scouting purposes - you can't use it as a cheap bomber or as a transport plane. Use it with care, as the Po-2, like any onther plane, obeys the Fuel mechanics of Spring:1944.