You can do an ITX build for basically any task these days, there's not really any downside for the average user.
The 250D is a solid choice if you plan on using a H100i (or similar) and need a full sized optical drive. There really isn't any competition for it at this point, so if that's the route you are considering then it's likely to be your first choice.
Positives
Looks pretty cool.
Window (if you like that kind of thing)
Decent graphics card cooling.
Fits H100i/similar.
Fits full sized optical drive.
Fits basically any power supply.
Fits basically any dual slot graphics card.
Negatives
Very big for ITX, especially in width.
Doesn't fit thicker radiators or support push/pull.
General airflow isn't amazing.
CPU cooler support isn't great - slightly limited liquid cooling options, very limited air cooling options.
Side exhaust means some motherboards aren't particularly well suited.
If you are looking for something small(er), or something that supports CPU air cooling then there's a lot of better options. It's a bit of a one trick pony, but it's a pretty good trick.