One thing i have discovered is, there is a lot of people saying things can't be done. Mainly by people who never thought of doing it that way.
With that said, the bike can and does work well for elk hunting, wether day hunts or packing in camps and hunting out of camps, but if you think you are going to buy a bike and go hunting off of it, is really naive.
A physically fit rider with good equipment can go many places. Todays bike packing gear is great. Now, the more technical and steep the road\trail is can determine the effectivness, I have found gated roads work really well off of a bike, but i have also used singletrack trails. I would rather use a bike any day of the week over a sideby side or atv, and i hunt where i can use the bike. But i have been mtn biking since the late 80's.
the bike does not matter as much as the rider, but i have used old cross country races bikes, what ever i had laying around, but the last few years, i built a bike for hunting and bike packing, front and rear racks, frame bag, pogies, basically lots of bikepacking stuff. I do ride bikes year round and find it fun, but like anything there is limitations, The biggest i have came accross is snow. A couple of things that you won't think of, sweat management, you will sweat climbing the hills to get into your area. Where do you leave your bike and do you lock it up? Wet brakes, they squeel loudly. Other hunters who just don't like you, because you are on a bike. This one is the biggest and causes the most issues.
One thing that i have found, is that animals, don't always know what to make of you. You have the silloute of an animal, but not really, but you do. Alot of times, they stop and look at you trying to figure you out. Think about it, your head sticks up and you have something coming out from behind you. So i say go for it and learn. All tools have there time and place, you just have to figure out what the time and place is for bikes and elk hunting. For me, it is all the time. I almost don't know how to hunt if i am not using a bike.