why add 2 seperate animation resolutions option, and not scale them instead? its just looks ugly/weird that there is all this space there and a tiny animation is played in the middle...
Because scaling them would make for some very messy code for one thing. There would be a lot of checks to make sure things
might look right, but no guarantees. Scaling them also means adding some sort of scaling functionality to the anim code itself and would only have to apply in those specific interface instances. And this scaling would be in addition to the scaling that the graphics code already does to support non-standard resolutions.
And, of course, what if the mod doesn't actually want them scaled up? Adding the extra hi-res files would be up the modder, scaling them in the code would be done whether you wanted it or not.
Adding an option for hi-res anims can be done in just a few lines of code and only the specific areas which you want this feature actually need any changes. That makes it far easier to support in the future as well.
*ANI may not be able to scale up by the engine, but maybe an EFF animation will work when scaling up?
There is no difference in how they actually draw though. All graphics eventually pass through the same couple of drawing functions, and those drawing functions are what scale things.