A question about DYI overflow

[BushFishRox]

I borrowed this from midnight:

now if that "simple" design can hold a syphon why is the DYI over flow so complex?

I am just wondering since I will be making some soon.

 

[rallysman]

because the simple one won't restart after a power outage and would be almost impossible to match the flow of a pump.

 

[ar0wan]

because the simple one won't restart after a power outage and would be almost impossible to match the flow of a pump.

THIS.

 

[midnight]

first pic is just a drain
not an overflow like the second pic
and what rally said