Not enough field of view to glass for critters at 45X in my view. It might be a good unit to check out antlers or horns once you found the critter with alternative optics as fixed eyepieces are generally very crisp. Also, 45X isn't useable in atmospheric conditions with a lot of mirage or when it is very windy and the scope is moving around. For my use, a fixed 45X would not work as I use 20X on my scope(s) more than >40X. I do like to have a scope that goes up to 60X for counting growth rings on sheep and looking at them at long distances when conditions allow. So, from my perspective as a Swaro 65mm owner, I like the 20-60X eyepiece and have no desire to own a high magnification fixed power eyepiece, (never having owned one).
As a bit of a comparison, I have a Nikon ED 50 for my small scope that came used with two eyepieces......a 13-30X and fixed wide angle 27X. Even though the fixed eyepiece is optically superior (I've tested it on fancy eye charts as well as watching California bighorns a mile away above the house), I choose the versatility of the zoom when the scope goes hunting, even though I give up a bit of optical quality.