Easy to find ammo for too... LOL. and about 10% higher pressure for reduced barrel life; published velocities lower than 6.5 x 55 (not by much) and not really suited for bullets above 130 gr. I would not consider it a moose rifle, and again, no benefits over the CM which is more available or the 6.5 x 55. It will run in an AR sized mag I believe.
any factory ammo shooters should know by now with the cycles that you stock up and keep on hand, couple suppliers I commonly use get it plenty enough I won't have to look for a long long long time, not sure how anyone would try and function like the old days only having a box and half on hand and then go look for another box a few years later? so...lots of 6.5 Grendel's sold in Canada, lots sell the ammo, you don't buy a box a time, you buy a case when it's in stock lol, and because they are so fun to shoot you keep a lot more around than you would a typical big game rifle, great range day fun, predator calling fun etc.
this is a 52,000 psi cartridge, so about 10,000 psi lower than most, they do that for auto-loaders, it's about the highest barrel life you'll find in anything that can smack deer at 400 yards no prob
yup it's 123gr bullet has about the same sd (penetration ability) as a 168gr 30 cal bullet...is that not adequate for moose? my bull moose at 125 yards went 15 yards, anyhow we meat hunt primarily now and not chasing giants on big dollars etc. so take that for what it's worth, it will work if you do your part and this sort of cartridge more people can do their part a lot easier, most rodeos happen with the guys who are over-gunned not the other way around
yes it's micro length action, AR length action (same as .223) cartridge, this is a drawback to the short action 6.5 CM, I agree the 6.5 CM is the most versatile cartridge available and would be the top choice for most, and the 6.5 CM also has excellent barrel life, way more platforms available for the short action, and you get higher bc and sd bullets in the CM to fight wind/drop further and penetrate deeper also, the 6.5 CM a solid 600 yard performer, amazing what I does for 41 grains of powder, but the Grendel is same for it's 30 grains of powder, realistically most will not shoot well past 450 (Grendel fits into this window with zero fat), few will be solid to 600 and very few are consistent past 600...so the Grendel actually falls inside 450 with zero fat
recoil energy is about 38% less with the Grendel than the 6.5 CM so that's a pretty significant point when talking about light hitters for the family

you're talking single digit ft/lbs recoil energy, equivalent to a 22-250, although feels like a .243 to me due to the heavier bullet push, you will not pull the trigger on a 6.5 Grendel and think it's a .223
if I was going short action, even though it hasn't taken off as fully as the 6.5 CM, I'd look hard at the 6 CM with 108gr factory ammo before the 6.5 CM in this particular ask, zero at 250 and call it day, it will become just about as popular as the 6.5 CM, it will recoil a little less and the fam will shoot it a little better, ruger predator in 6cm, chassis with adjustable butt stock, the Trijicon green dot scope...also an awesome choice but barrel life will be a factor if shooting a lot
so yes the 6.5 Grendel has some key of benefits over the 6.5 CM for this ask, recoil champ, watch more in scope, barrel life closer to a .22lr than most any other 400 yard capable big game cartridge, meaning lots of practice possible due to light recoil, barrel life and affordability, the factory ammo quite a bit less dollars than the 6.5 CM/6 CM ammo
it is hard to beat the 6.5 CM, but you can specialize really well with a couple other 21st century winners, the 6mm-ARC too new to recommend but it will become a darling option soon as well, it's basically a 6mm Grendel, just as the 6 CM is fast becoming a darling as well, for recoil and watching in scope advantages over the 6.5 options...some mpbr advantages also