My Musical Fidelity A5 Int Amp also has HT Direct that completely bypasses the preamp section and applies the inputs from my AVR preouts directly to the amplification section.
There is one benefit to this type of 'true' bypass as opposed to simple unity gain thru the preamp section.
IF you have a sub that has both LFE inputs and line level L/R inputs, you can have a sub for both AVR (with the sub output from the AVR to the LFE sub input) AND 2-channel (with preouts from my A5 int amp) without the need for swapping cables or some sort of switch in front of the sub.
I have this setup in my hybrid HT and 2-channel system; works perfect.
There is one benefit to this type of 'true' bypass as opposed to simple unity gain thru the preamp section.
IF you have a sub that has both LFE inputs and line level L/R inputs, you can have a sub for both AVR (with the sub output from the AVR to the LFE sub input) AND 2-channel (with preouts from my A5 int amp) without the need for swapping cables or some sort of switch in front of the sub.
I have this setup in my hybrid HT and 2-channel system; works perfect.