if you are WOH points constrained, this devaluation only means that you've lost an easy way to buy more points for ~$0.013 each.
so, let's assume you would normally buy 50K points/yr using the points+cash method at the $0.013 rate or $650 total.
now, you instead buy these 50K miles directly from WOH during their annual 40% bonus period at the rate of $0.017 or $850 total.
the devaluation costs you $200 a year.
cash rates irrelevant.