It's certainly eccentric but he's not on his own.
Mani from the Stone Roses, during the recording of 'The Second Coming' VOLUNTARTILY worked in the closest Woolworths to the recording studio, even though Geffen had just paid the band a $10,000,000 advance - which in 1993 was quite a bit.
People do strange things to keep their feet on the ground even if they no longer need the money
EDIT: Mani enjoyed it so much there, he married one of the check out girls #rockfact
DOUBLE EDIT: Maybe that's why he worked there voluntarily!