[Elecraft] IF OUT - Same as just sharing the antenna?

[JHR]

Please help me understand how the IF OUT works on an Elecraft radio.  Is 
it the same thing as sharing the antenna with a T/R switch, or does it 
tap the RF processing chain later down the line. Does the IF OUT merely 
share the antenna, or does it come later in the circuit - are there any 
practical reasons why one is better than the other?  I presume the IF 
OUT is better, but wonder why.

[It matters and will settle a bet who eats steak and who eats hot dog.]

Thanks in advance K8JHR