Besides what we have mentioned above, I presume you can use non-Wyndham credit card as long as you book through Wyndhamhotels.com and accrue points under WR?
I plan to use HH AmEx, same points accrual (yes point values are relative), Wyndham Rewards credit card isn't all that appealing and isn't even worth applying at this point (I don't like too many credit cards opened at once). It's at the bottom of my list.