Absolutely, and I wouldn't carry a light-colored bag without first treating it with Apple Rain Guarde. It protects the bag from water damage but I also think that it may help protect it from dirt and even color transfer - but I don't know that for sure - just my opinion.
I don't have the Beechwood Mercer bag but I recently gave my new Grey Birch Willow Floral Nomad two applications of Apple Guarde and it was fine, and I have treated other light-colored bags like my Putty Sophia without any problems.
Have you used Apple Rain Guarde before? I order it on Amazon. It's an aerosol so you should apply it in a well-ventilated area. If the weather is warm I take it outside to spray it and during cold weather I hang the bag in the bathroom and turn on the fan. I thoroughly spray the bag, then wait a half-hour and give it a second treatment. It doesn't seem to have any affect the bag at all but I always wipe down the hardware with a damp cloth after spraying a bag - just to be safe.
Here's a link to an old post when I put the Apple Garde to the test and was very glad that I had used it to protect a very delicate, natural, straw coach bag, my Bonnie Convertible Tote. The bag is made of straw but it's very finely woven, more like linen, and she cleaned up beautifully thanks to Apple Rain Garde!
https://forum.purseblog.com/threads...thank-heavens-for-tpf-and-apple-garde.693646/