Whats the point of having a command chain?

[SchDerGrosse]

As the title says.

Apart from very minor in game effects (eg units tend to scoot towards their HQ, or telling arty to support units under X HQ etc.), as far as I see, there is nothing that would prevent me to just put EVERYTHING under the highest lvl HQ with the biggest command range and be done with it.

No HQ overload, no organizational penalty, no difference in HQ commander effect. Nothing.

Am I missing something?

[SgtZdog]

Yup, putting too many subordinates under an HQ does apply an additional order delay penalty. It will also force you to have your HiHQ closer to the front where it is more likely to get ID'd and killed (which will apply a massive penalty to you). We also have maps/scenarios where your HiHQ will not have sufficient order range to cover the entire front and so trying to do this will result in units being beyond the command radius.

So while it can be an interesting idea, don't do it, the game will both directly and indirectly punish you for it.