For mountain spot & stalk they are an asset, not so much for treestand hunting.
For treestand hunting 20 feet up at 20 yards will only be about a 1 yard cut, but a 50 yard shot down a mountain at 30 degree angle would be a 20 yard cut. In other words to hit the target you would need to shoot your 30 yard pin.
I started using one a few years ago and I really like it. I feel a person can judge distance pretty good out to 25yds with some practice. When you get beyond that and factor in the the varying heights of stand placement with the dip in terrain it becomes complicated in my opinion. Thr range finder I use has the angle compensation and when I check the range from time to time I get surprised and I have been bowhunting for s long time. The one I bought was the chuck adams edition and it was on sale for $149. It makes you so confident and that makes you a better shot. I also think it is real handy when hunting at field edges as its hard to judge distance accurately on open fields. What I would do is try and find someone who has one and see if you can borrow it for a couple days then you will know if you need one.
I very seldom ever range a deer when hunting. What I do though is when I first get in a stand, I will range various objects where I expect the deer to be, so I know ahead of time what the ranges are. It seems like most of the time when a deer is in range, I either don't have the time or don't want to make the movement to get the rangefinder. Like someone said above, they are especially handy when hunting along a field. When hunting in the woods it seems like most shots for me are under 25 yards anyway.
In my opinion for achery hunting they are well worth the money.
Range finders are a great tool especially if you do not spend a lot of time shooting at unknown range then check to confirm you estimate.
When I first started shooting archery I walked 2 miles to work every day and I picked out a distance made my guess then stepped it off to see how close my guess was to being right. I changed the objects every trip. I did this for a couple of years in addition to shooting at unknown ranges. Back then in the 70's compound bows were not as fast, arrows and broad heads heavier and 3 D was just emerging. Now that I am older and shoot less poundage with aluminum arrows range is still critical to me.
To address your questions. I feel for PA archery hunting from the ground or tree stand a range finder is well worth the $$ and can be a diffident asset in making a good shot when it counts. However I do not believe the range compensator is needed for typical PA hunting. I do not feel there is that much difference in the POI at reasonable archery hunting ranges and angles.
Like stated above I also range the distance to fixed objects such as trees and stumps when I first get into a stand (after estimating the distance) and keep that information in my mind as the game approaches. I range the distance within my shooting lanes and wait/hope the deer will proceed to an area of know range an in the open for a high percentage shot.
I seldom hunt fields but if I did and I was concerned about the range I would probably step or measure off the ranges and mark them with a small branch preferably one with leaves.
In addition to ranging and keeping to shooting within my personal distance I also range longer distances than I shoot just in case I might make a shot at a known range and the deer being hit should run to a longer range, stand and give me a second shot. In almost 40 years of archery hunting this has never happen yet. However, I have prepared for this opportunity.
Spend the money for a brand name rangefinder and save by not purchasing the unit with a range compensator. Also save my not paying extra for a camo unit it is not need. Above all else if you hunt from a tree stand practice from a tree stand.
I think the angle intelligence is worth it. Many rangefinders have the feature anymore, its not alot more money, and its nice to have even if you dont use it/need it for most shots. You dont need a real expensive one for archery since the distances are short (compared to rifle). I think many people who haven't used the angle intelligence would be suprised at the difference under certain circumstances. A treestand on a hill side, shooting downhill, can create quite a steep angle and effect the shot. May mean the difference between a leathal hit or a miss, or worse yet wounding an animal.