Why does Joe Pass substitute minor 7 chords for dominant 7?

[Christian Miller]

Why? Because it sounds good.

[Boss Man Zwiebelsohn]

It would actually be a good exercise to loop a dominant and play over it for a long time.[...]

Maceo Parker en Argentina - Festival Telecom - 2007 : Archivo Humano : Free Download, Borrow, and Streaming : Internet Archive

[Jazzjourney4Eva]

ii is just V in second inversion.

but why bother?

[Glin66]

Hi everyone!. Just a question: Why does Joe Pass substitute a min7 chord for a dominant so the original I-vi-ii-V7 progression: Cmaj7-Am7-Dmin7-G7 ends up like this with this substitutions: Cmaj7-A7-D7-G7. Anyone?

The substitution of a minor 7th chord for a dominant 7th chord is a common technique known as a tritone substitution.