As we saw in our benchmarks, NVIDIA's GeForce GT 520 is clearly not good enough for any serious gaming. If you are willing to sacrifice details settings, down to lowest in most games I could imagine things being playable at 1024x768, but not beyond. Decent cards for gaming start around $100 with GT 440 or HD 5750, which means $40 more than the GT 520. So instead of going with such a low-end card the better choice would be to buy one game less and spend the saved money on a decent graphics card like the GT 440 or GTS 450.
ZOTAC has chosen to use an active fan on their card which seems unnecessary given the low heatput of the card. In addition to that the fan profile does not seem to be well optimized either - the card emits as much noise as other much powerful designs. GT 520 does offer solid media playback functionality, but this can be found on previous generation cards, too, at a fraction of the cost. Even modern IGPs like AMD's Fusion or Intel's Sandy Bridge have decent HD acceleration capabilities which doesn't add cost or noise.
One possible scenario would be if you plan on using a multi-monitor desktop work setup, which the IGPs can't provide due to lack of sufficient output connectivity or if you have a P67 or X58 platform without integrated graphics. On the other hand, for this purpose, any previous-generation card with multiple outputs will work just fine. Considering all this, it is difficult to find a clear use case in which cards like the GT 520 or HD 6450 can justify the substantially increased cost vs. older cards or integrated graphics.