AudioEngine A5 hook-up question

Using an Apple Airport Express into the back of the left speaker, and streaming music wirelessly from my MacBook Pro will be really convenient, and should sound mighty fine. USB cable from MacBook Pro into an HRT Music Streamer II, then RCA analog interconnect cables to the left speaker (via the "Y" adapter) will give better sound. BUT.... is the improved sound of the USB DAC set-up that significant as to "overtake" the convenience of the Airport Express set-up ? Any thoughts ? My critical listening sessions are done with my main system (see my system.) This new computer set-up is for "background listening" while I'm working in my upstairs library.