The DPDT switches the two windings from series to parallel; both windings are always used.
Your suggestion doesn’t do the paralleling, so doesn’t have as much current capacity. (Whether the extra current is needed, I have no idea.)
I see. I'm not sure paralleling a transformer output like that is correct, unless they'were winded together, ex. like stranded wires.
Wouldn't any slight voltage difference cause the windings to fight each other and cause current flowing?
Maybe not that critical (don't want to think like these old grunts) , a transformer output quickly voltage normalizes with any small load...
The C470 has 7ohms, takes 7Amps @ 48V.
C245 would take about 10amps peak at 24V, but would heat so fast that I doubt it could cause any overheating issues.
But yeah, free extra current for anything