It might be just me but the current vogue amongst young singers for singing songs to the drone of a Shruti Box - effectively one chord - seems to be a retrograde step. If a song can be sung to one of those contraptions then to my ears it would be better sung unaccompanied.
The only advantage of a Shruti Box would be to hold a singer to a key when they might otherwise drift.... but that is not necessarily the end of the world in traditional singing. Listen to Sarah Makem singing I Courted A Wee Lass (The first track on Volune 1 of "The Voice of the People). Her pitch shifts slightly up and the over-compenates drifting down below her opening pitch. It is still a magnificent example of traditional singing.