Yes, that is a fast way to replace fork oil. Though you won't ever get it all out, and there is no way to determine proper and equal amounts in each fork unless you remove springs and measure air gap.
Once the forks are off taking the caps and springs off takes and addition few minutes, so why not?
2010 690 EnduroR
2013 500 Exc
20+ years, 100k+ miles, 15 state's, 10 Countries, 3 years on asphault looking for the checkered flag, 7 dirt trying to stay on my minute.