The knife on a keychain is commonly accepted, the offsetting negative I've experienced in the past was that the heavier the keychain the more quickly the lock cylinder in a vehicle wore out and caused issues. Learning my lesson (and having replaced at least 3 locks over the years) I minimized my keys down to the barest needed. One house key - the doors are keyed alike, it's in a keyway only available from locksmiths. All other household keys - garage, toolbox, padlocks, etc are in a secure location at home. The ignition/door keys for the two family vehicles are next, and locks on them - hitch, gas cap, trailer etc are in the vehicles where other family members who use them have the needed access. Not on me, while they are on empty at a station 20 miles away and using a crowbar to pry off the cap. Another lesson. These days it's still bulky with one chip key and a fob, but the fob car doesn't have it hanging off the dash, and it does have a door key. The chip key truck also has a door key hidden on it. I have spares, and if I lose my keychain, those are ALL I lose, not every lock I own. Stolen keys are like stolen Iphones - do you want someone who know's whats up to have access to all your stuff? Why, yes, I did sell security hardware at one time, and read the FM on Security, and worked as an MP in a confinement facility not inside the US. Keeping the keys separately located increases the time spent breaking in and that is a real deterrent.
Now, we were talking about carrying a SAK, I've owned quite a few and even have a Champ for sale in a flea market booth. My first criteria is that it doesn't have a cap lifter - don't need or want it. Now, a lot of others might prefer one, however, there is a large number of us who see it as useless, and in recent history the inclusion of a cap lifter in EDC tools has been a significant fad. For my use, I have more important tools that rank higher in priority. SAK's tend to have small almost delicate blades, which is a negative.They should be 3.5". The scissors are usually outstanding, and make the list. A clamshell opener hook is another when I was working retail. Awl for wood working in the field, yes. Can opener? Not since we moved to MRE's and that really dates me. Field rations have no cans now, it's less useful than a cap lifter. Wood saw blade is more important. A good flat screwdriver and the modified Phillips is handy. Tweezers, yes if they were pointed, not square. Toothpick can be ok, and one last item, a pocket clip. G10 scales, in blue, classic square crosshatch. MIltary, in coyote. Hole for lanyard and the main blade needs a lock.
That SAK doesn't exist as far as I have searched. So, I don't carry it. I live with my lowly status trying to make up for my inadequacies by having a good 3.5" bearing flipper with G10 scales and a clip, knowing I may have to delay or take the long walk to a tool box where I will find the full sized version that will do the job better and be inconvenienced doing it right the first time. Such is life. I have a truck tool box which comes inside frequently.
I have SAKS close to what I want, I might pack one in the shave kit where it lives in case I need to trim nose hairs or such. In it's place, in my EDC, I carry a small USB recharged LED flashlight, in blue, to see (and to see when it gets dropped) in the dark which is used more than a pocket knife. Funny how that works as you get older.
SAK needs to get a line of more modern, larger sized knives which meet more abusive conditions of use, and get their pricing aligned with those who need them. They have strayed far from their roots as a military field tool which supports a soldiers rough existence in the wild. Kinda like $120 Carharrt pants - few contractor employees can even afford them now. And that is another reason I don't carry a SAK - I don't need to dress up my keychain. It's already too big with a fob and less is more.