for real... are all the weapons in the game useful?

You need to focus on your game experience, you can use all weapons(All of them are playable), but playing with them depends on you and your experience.

yeah because if you have bad weapons you cant really play with them

Yes, all weapons are useful, some just are more popular and better to play than others. It all depends on your determination to learn sprays to certain weapons.

Most of the time you will use only 5/6 types of weapons but different players will use different guns.

I have bad weapons you cant really play with them in real live

M4A1 and Glock, the best weapons in the game. I really like it.

They are all useful, the shotgun is quite good i usually use them when 2nd round after we lose round.

Galil and Famas is pretty too if you want to full buy with smoke but can't afford the AK-47/M4

i like smg and shotgun, but my elo is gold ahahahaha, i can't play with rifles because im so bad

No, the negeb, aug , ssg is not usualy, shotguns too