No, it's not. Just because its all you use, doesn't make it the best.
If that were true, then wouldn't EVERY gun be the best gun (thus NO gun is the "best" gun) since at least 1 person somewhere probably has the most kills from one of the other weapons in the game? lol Like, I'm sure someone has most of their kills from the SC2010, another has the most from the M14 EBR, another has the most from the Bizon, another has the most from the Chain SAW, and so on.
Actually the best thing I find about the Honey Badger is it's size.
It is compact. There are SMGs that dwarf its size - especially silenced.
Look at your squad members sometime and just check out the difference in gun size.
It feels as if you stick a silencer on most weapons then you're toting around a broomstick 5ft long. And you know that sticks out around corners and away from walls to give away your position.
The Honey Badger also has the built in silencer, and the iron sights are easy to use - thus for most players an extra attachment perk is unnecessary. Equipped with Grip and Extended Mags the Honey Badger becomes a very player friendly weapon. Equipped with a tracker sight and the Honey Badger becomes a noob's best friend.
I like to keep at least one HB class as an in-game fallback for when connection issues appear to be limiting my silenced weapons effectiveness and I don't want to use a "loud" gun.
When my bullets don't seem to register and I am dropping with one shot, my usual tactics are to try the following steps;
1) Get sneakier and shoot more people in the back
2) Up the rate of fire and spray more (front or behind the bad guys)
3) Go loud to increase the weapon range
The HB seems to work silenced for anything more than Shotgun/SMG range when other guns don't. The fact that you can stack so many good attachments on it make it too good not to use. You don't have to waste an attachment to make up for a deficiency. The camo challenge for 150 no-attachment kills with the HB is the easiest one in the game.
However, while I have done well with it, it is far from my "best" gun. If I had only one gun to use for everything, the HB would probably be the best choice, but if I had only one gun to do well with, it would probably be an AK, Remington or SC-2010.
It's not better, really. It's just easy.
And you know what?