I think there's several members on here that do the same thing. I've thought about it too(instead of one of the extra bedrooms I'm using now), but when you enter our home you enter the living room(our home is an open concept floor plan). Maybe I should use the family room instead.
When I lived in Indiana, my living room was completely closed in and that would have been perfect for a sewing room.
If your DH suggested it then go for it!!!