I currently work as a outdoor guide and thought about this track too. My situation isnt exactly the same, but take it with a grain of salt.
I too, thought about getting my WEMT, but staying predominantly in the guiding worlding. Talking to my boss, who has 15 years as a full time Outward Bound Guide, he advised against it. Without clear documented EMT hours to help with re-certification, I did not want to re-certify every two years. The WFR re-certification is only a weekend, while the WEMT re-certification is relatively much more expensive and longer (weekend vs. week long if I remember correctly).
In the end, a WEMT would be nice, but for my current job (guiding week/month long trips), additional outdoor medical knowledge it is not necessary.
My boss also briefly mentioned guiding with WEMTs and their opinions about their WEMT. The Outward Bound guides with WEMT just let their WEMTs expire because of the cost and duration assoicated with re-certification.
But if you want to pursue WEMT for personal reasons, go for it. I am sure you'll learn a lot and may save someone's life.
But, at this point in time, I do not think that a WEMT is worth the time and money to maintain a WEMT.