Currently OPFOR have no counter to the BLUFOR Rhino's ATGM missiles.

The T-14 Aramata which the T-140/K Angara is based on has the ability to fire 9M119 Svir/Refleks missiles from it's main gun, which is common to T-series Russian tanks (T-90, T-80, T-84) and the Serbian M84-AS.

There is also a longer range ATGM designed for the T-14, the 3UBK21 Sprinter with a reported range of 12km/7.4mi.

The 9M119/Refleks and 3UBK21 Sprinter require a laser designated lock on, the Angara does not have a laser but does not require one as other OPFOR assets can provide this laser designation - the same is true of BLUFOR's Rhino which relies on other assets to laser designate for it.

By adding these munition's and the ability to lock on laser targets to the T140/K Angara while using 9M119/3UBK21 munitions it will give CSAT/OPFOR the ability to counter the Rhino's extensive long reach via it's ATGM's.

The benefit to adding this munition to these tanks would add balance to game-modes such as Warlords where entire round's/mission's can quickly become stale-mate due to domination by Rhino's and their ability to hit anything which is laser designated including targets far beyond their visible range.
Additionally with the Rhino's low heat signature they are essentially invisible to OPFOR land assets, by being able to spot, designate and hit such an effective BLUFOR asset with armour which is more than capable of doing so would bring added realism to the Tanks DLC.

If this were added you could easily add a 3rd T-140(type) to Arma 3 Tanks DLC where it swaps out one of the HE or HEAT munitions in favour of ATGM munitions.