Tachanka doesn’t have too many operator combos but I can think of some. So the advantage is you can immediately get off the LMG and not get shot while crouching. When you crouch and mount the LMG (still don’t stand) when you get off the LMG there is no animation from stand to crouch.
There isn’t any tricks for him as such *cough* click bait *cough* but I guess there is one. They are quite self explanatory for I won’t go into the obvious details.
The two styles of gameplay you can put together are ROAMING and SPAWNPEEKING. Disadvantage: There isn’t really a disadvantage as you can move it wherever AND if you use this correctly.