G'day Mate,
I would rather have 2 switches & 2 batteries, so if one switch or battery failed, which can happen easily, most electrical failures are open circuits, not shorts, I have another backup switch & battery.
I am an electrician by trade, so I know about redundency, in the hospital, where I work, we have 2 high voltage power supplies, & an emergency generator as backup, plus UPS power supplies, so I use the same principle of redundancy, especially if it can save my plane.
Just my opinion, since I have lost planes recently. from failed batteries & switches, & that was before my DX7.