Notice all the ex-Varig drivers in EK take the effort to keep the brakes release "quiet", where the sop's say there is no requirement.
The EICAS message disappears, yes, but the bang is nice to confirm with all in the flight deck, not just the FO, that the brakes release has been performed, whilst no visual identification is required. Especially good during LVP whilst all eyes are outside or on the EFB!
halas