This is just my opinion. I think every airgun should have a cocking indicator, as well as a anti double feed mechanism! This goes needless to say why, but what's your opinion?
Anti-double feed is a great feature. The only guns I have it on are my Pulsar and Renegade, but unfortunately Daystate's new magazine design does not. I altered the old magazines so I could keep the feature; to me it's that important. I wish all guns had it. Knowing when a rifle is cocked is a good idea too, IMO.
Yes these would be nice features. I definitely try to never leave mine cocked. If I’m hunting and don’t get the shot I just fire the shot eventually in a safe direction. However, I definitely have found myself unsure and pointing the gun in a safe direction and pulling the trigger to see if it is cocked. As far as double feeding I’m a forgetful dope and have never done it (knock on wood). I’m my opinion it’s super easy to avoid.
On my FX Royals, if my safety won't move fully to the rear (safe position) then it's not cocked. You can adjust the trigger to make this work. Also if it is cocked if I pull the cocking lever back it feels different. I always chamber a pellet after making a shot. Habit.
While a cocking indicator is a nice feature to have, I personally don't trust them and double check for myself when I'm in doubt. Treating your airguns as firearms goes a long way in regards to safety. Although, some airguns are different. There's no way to extract a pellet/slug unless you shoot it in a safe direction or push it out with a rod. I do like having an anti double load feature but I always find myself checking a second time and knowing what condition my airgun is in.