I'm afraid I must respectfully disagree with our moderator. It very much depends on your on personal skills as to whether archery is a lot more challenging than hunting with a revolver.
With today's compound bows and holographic sights it's a whole lot easier to harvest a whitetail than it was when I started learning archery 50 years ago. I admit I haven't done it, but I can easily see being able to take a longer, cleaner shot with a compound bow/holographic sight than with a Walker using the hammer notch and bead sight. And I'm a better handgun shot than an archer.
In either case, tracking/stalking/camouflage skills are very important. Assuming those are all in place it comes down to how well you handle the weapon of choice, and the bow has a lot of advantages over the Walker for the AVERAGE sportsman.
Now, there are some people who can shoot a gun a LOT better than they can shoot an arrow, and they might not be able to take advantage of the compound bow/holographic sight technology, and for them the Walker would perhaps suffice.
It's just as true that there are people who can put an arrow into a soda can at 75 yards but can't shoot a 6" group at 15 yards with a big bore handgun. Obviously, they'd want the bow.
My point: the choice of bow or Walker is really made by an honest evaluation of personal skills because they are so very different. It's not clear that one is inherently much more challenging.
Anyway, that's my opinion, which is worth about half what you paid for it....