Actually this amp sounds best at (small) gig volume, played on the clean channel, with the volume around 5. It's still a clean sound, but it's just beginning to overdrive; I suppose it's overdriving the power amp - I'm not really much of an amp expert.
As long as you can find the right setting (somewhere around 1!) on the master volume, it can produce a decent sound at home too. I also have a Blues Junior (15W), which I rarely use, as I just don't find it sounds as good (or as versatile) as the good old Blues Deluxe.
I was told a few months back that the reason that most Fender volume controls have most of their effect in the first half of their travel is a policy decision many years ago to make them sound louder than comparable Marshalls. I was told that if you turn a comparably powered Fender and Marshall up to 5, the Fender would be louder, even though turning it up higher than 5 won't produce much increase in volume on the Fender, because it's already at 75% volume when the knob is turned up half way.
I don't know if it's true or not, but it does mean that they can be fiddly to adjust to get the right volume for playing at home.
I've wondered about attenuators, but I don't really know enough about them :-?