Asus putting solder but not a chip on this spot on its motherboard so you can have a heart attack when you notice it

Is that the chip that makes pictures have more than 3 pixels?

Sorry. I just cropped from the picture asus had on their website

It's not unusual for a board manufacturer to design a single board with a few different configurations of components, and simply not populate the ones that aren't needed. Margins are super slim, after all, and they would not hesitate to omit a part that might only cost a fraction of a cent.

I can't see from the picture what it is, but it could be some power related thing, and if the feature is not the board you wouldn't need it's power generator either.

That's not the problem, there are other 'missing' components on the board too but since there's no solder in their place they're not alarming. The problem is that this particular spot looks like there was supposed to be something on there
- I can't really tell from the picture, but from the looks of it there is a large solder pad with four smaller pads beside it. It's possible that it is a voltage regulator or other similar IC that has a large ground pad (for a heatsink) and four smaller pins. All of the pads probably have solder on them, but the large pad is the most obvious.
  
  There are all sorts of reasons why a manufacturer would leafe space for a part, and then not use it. It's possible that regulator is providing power to a part that is also not populated , or that the part that it powers has been redesigned to not need that separate power rail anymore. Designing a board like that is expensive, so if some parts are no longer necessary, they will just remove them from the build, and save actually taking the part off the board for the point in the future when they need to redesign it.

Wave soldering machine - they basically suspend the whole board above a vat of solder, it bonds anywhere it can. So if they don't need that chip on this model, it's getting solder anyway.

There are other empty spots without solder on them tho
- Anywhere that's not masked on the board will get solder. Anywhere.
  
  Some IC's are electrically or thermally bonded to the board, e.g. MOSFETS and other power handling components, which is certainly what would have gone in this spot. The part where the MOSFET's heat spreader would touch the board is not masked, ergo it gets solder on it. Your other missing-chip spots definitely have solder on their connecting pads, where the pins for those chip(s) would go.
  
  That's just how it works. This is not unique to ASUS or any other manufacturer.
- They only put solder where some models need connections. Your cheaper model is missing some part.
  
  Soldering the whole board would make it defective.
- They should be. Are you sure it's not just a really thin layer on the smaller pads?