That depends on who the country is at war with. Against talib insurgents, helicopters provide the best CAS at a fraction of the cost at which jets can. And they can do it a lot better - a jet will have to make several passes and probably still not be able to spot individual riflemen on the ground. OTOH, a helicopter can linger over the battlefield and pick off enemies at will.
In an insurgency like the one in Afghanistan you need all the advantage that you can get. There are multiple scenarios where you will need fighter jets. I will give you some examples to let you understand. Obviously your understanding of intense guerrilla insurgency is limited. So let me help you here.
1) Insurgency is about hit and run attacks. What an insurgent force want to do is create dominance over an area that it targets. As a regular army you will be tasked to main check points, maintain garrisons and have logistical nodes. They are all prime targets for an insurgent force. They will attack with more and heavier forces than are deployed at a checkpoint or a small remote garrison. Here every second counts, by the time you scramble helicopters it will already be too late. Helicopters are slow moving and carry less fire power. A fighter jet on the other hand is faster thus will take less time to get to any given area drop bombs and clear larger areas. It also will carry heavier weaponry.
2) Helicopters are more prone to ground fire. Combat fighter/bombers on the other hand being faster and especially when using laser guided or satellite guided munitions fly a lot higher. Thus are less prone to ManPADs and AAA fire.
3) Helicopters won't be able to perform air defense duties. You need fighter jets to defend your airspace and deny the enemy the use of your air space.
These three points are just a starter for an argument why it's better to have fighter jets, fighting any conflict. And thatswhy Afghanistan desperately needs jets like LCA or Migs.
Americans fight in a very different way - they don't mind shooting a hellfire missile to kill one insurgent. Other countries cannot afford to do things that way. ISR (against insurgent riflemen, not enemy radar complexes), medevac and logistics (transporting soldiers and material) are all best done by choppers, not combat jets. In fact I don't see how LCAs or migs can do any of those at all.
Now I will come to your point about ISR, medevac and logistics.
You seem to have a very limited idea about guerrilla warfare. ISR is not primarily there to identify individual rifleman ( although in a firefight you try and identify enemy lines with it). It is your eyes and ears over areas which are either contested or denied to you. ISR assets will fly high and will give you info about enemy activities both on the ground and on the airwaves. Insurgency is not about battle lines. You want to know where is going to strike, where it is going to plant IEDs, where it is getting it's supplies from and the routes its taking and for all that you need ISR assets.
Medevac is done in the field by choppers but only till field hospitals mostly. Same goes for logistics you will need choppers for the proverbial last mile but from airbase to airbase it has to be done with cargo planes.
Russia can ship tanks directly from Russia to India. They don't need to drive them through another country. But Afgh is landlocked. So we will need to transport by sea and then by land. It is simpler and cheaper to pay Russia.
For tanks. Russia will have to deliver it through third countries i-e Tajikistan or Uzbekistan the same way India will have to supply it through Iran. The route is not that different. The only real problem is the availability and reliability issues of Indian assets as was identified by @
Tshering22
and secondly Afghan army tried once in 1980s but were badly fucked by FC and Tribal people
