What if it is snowing and your laser rangefinder doesn't work? You can still range at any power instead of having to dial to maximum power to range then dial back down to take your shot. This takes time when hunting. You could have the trophy of a life time move out of sight before you can shoot.
For the most part with the exception of 1 or 2 Loopys and a NF, USO which is the only real US made on this continent uses them exclusively (my favorite optic). All of the Best Of Class Scopes from Europe use FFP. Not going to go into the specific merits of FFP but here are advantages.
Tom---I found this to save me a lot of typing Plus----when you have the reticle using more moving parts to keep the reticle size the same it is adding complexity and this means more can break.
Europeans prefer first plane scopes because they legally and normally hunt a lot later than we do here, and larger reticles are easier to see on a target. First plane scopes also cannot change point of impact when changing magnification because the reticle does not move. The focus for the reticle and the parallax adjustment are such that when you change the parallax setting on a first plane scope you will sometimes lose sharp focus of your reticle. Therefore, most European scopes have a fast-focus eyepiece. This is for the reticle and nothing else. Most European scopes are also built on 30mm tubes, many of them steel instead of aluminum. They are in general bigger and heavier than their American counterparts.
First plane scopes with rangefinding type reticles may be used at any power. European glass is second to none. Second plane scopes or "American" scopes are smaller and lighter and can have point of impact change when changing magnification, and many of them, especially less expensive ones certainly do. The parallax setting on second plane scopes has nothing to do with the reticle focus, so fast-focus eyepieces are a matter of convenience and pretty much a useless feature. Set it once properly at high power and leave it forever. Second plane scopes also have a smaller appearing reticle on the target at high power than low power, which is extremely important for precise shot placement. Second plane scopes with rangefinding type reticles are designed to be used at one power only. BDC reticles are not excluded from this. Traditionally, second plane scopes are one inch, but 30mm tubes are gaining popularity rapidly. Most people think that the larger tube offers a brighter image, but this is not true, although it may in some cases offer better resolution. Steel scopes are a thing of the past here. Also, all of our glass is imported, with no exceptions I am aware of on magnified scopes."