Well that's just silly. That suggests that the B. supernova would be about 70% of the brightness of the sun. We would then experience either two suns (albeit one slightly dimmer) during the day or a 70% bright night, depending on the rotation of the earth.
In sum, we would likely be in a state of near perpetual light.
"And every eye shall see him..."
Betelgeuse is intrinsically 60,000 times as bright as the sun NOW. The following is from MadSci.org (remember negative magnitudes are brighter when referring to stellar brightness):
The sun has a magnitude of -26, the full moon has a magnitude of -18 or
so. Sirius has a magnitude of -1.5 and is the brightest star in our sky.
Sirius is also one of the closest stars at 2.7 parsecs (about 8.5 light-
years). Betelgeuse is about 500 light-years away and has a magnitude of
about 1. Depending on how much of it's energy is in the visible spectrum,
it would probably be bright enough to rival a full moon. Somewhere in the
magnitude range of -18 to - 20. We would definitely notice it. It could be
visible during the day for several weeks possibly even a month or two. It
would be visible at night for several years.