I agree with you, but some people might want extra capacity for warning shots. There's a topic for another thread.
esstac cards, on my 940 the 5-shots are perfect, one on the side of the action and then one on the butt stock...I took the one spacer out of the butt stock so lop is around 13 3/8" instead of 13 7/8" it came out of box and 5-round card is perfect fit on the 'camo' non adjustable portion of the butt stock. So you can load it before you walk and then there's 10 more on the thing for topping up anytime you like. esstac cards can be had in 4-7 rounds, but 5-shots work perfect
and correction, the 940 pro 5-shots are 4+1 (2 3/4") not 5+1....unless you can ghost load which I haven't tried, 5 is enough, if you can get all 5 off on a 40 yard bear charge you might be named Jerry lol, so 5 in it, then 10 more on the action/stock is 15 rounds of grab and go nasty, the challenger magnum slugs are 2 3/4"
the 4+1 keeps the gun nice and trim and light, have a look at a 940 pro turkey 18.5"...mine is sitting with holosun eps, Carlson extended IC choke, 2 esstac 5-round cards with no ammo, just bare at 7 lb 1 oz and it's just over 39" long, it's a handy light feeling little thumper, not sure what it weighs with 15 rounds of slugs on/in it but it will help in the recoil management for the first few lol, probably help it get under the 30 ft/lb range...so it's nice to have that flexibility by starting light and still being handy carrying 15 rounds, probably like a naked bare m4 which will be a tank with the extras added
as a final note, warning shots I wouldn't bank on, ran into a guy fresh on trail after being run out of a spot by a grizzly that chewed on his tent in the night and he said they did nothing, 7rm into tree beside its head at 30 yards...nothing, he did say the only thing that seemed to scare him and keep him at bay were the digital alarms he had, one on his phone he rotated with a separate alarm he had, those sounds worked, the warning shots did nothing...not sure I'd have played that game and I have a feeling that same bear was the one the very next year in same spot that created a book called 'mauled'....that's a derail, that bear should have been shot right then and there imo, it stayed with him from 11pm to about 3am, he was in a non motorized area with his quad half way in so maybe that's why he didn't wanna shoot it? anyway, I wasn't camped too far from him when this went on and not sure I'd have done as he did for 5 hours in the middle of the night with this thing circling at 30 yards the whole time....it finally left he fell asleep for a bit and saw bear laying in sun on slope above him and he said that's enough, packed up and left, his quad was overheating and limping it out, I caught up to him on foot and my mountain bike the half way...my bike parked where his quad was lol...so I got the first hand account of why he was heading out early, I actually stalked a good dark loopy ram that morning to 50 yards and spent time trying to make him legal...some days you just never forget, a lot went on that day lol