It has been replied by RR .
indeed you can do trade like that but then you faild altogather to understand the significance of long and short routes and the cost involved.
Man please enlighten me regarding the cost when 1 lac shipping liner used to transit through the Indian ocean without bothering about the cost and on the top of that had India bother about such a marginal transit cost then India could not attain such soaring economic growth, since India's export trade all this years is solely transiting through the Ocean.
Afghanistan is more dependent on Pakistan for all kinds of trade hence it will harm her more if some of moroons continued to listen to their Indian masters.
The Afgan Government is keen on lowering the its political and economic depedance on Pakistan, as its core is made up of the urstwhile Northen Alliance leadership.
Landlocked afganistan has been so far been highly dependant on Pakistani ports for its trade. But access to chabber will give it more option to govern overseas trade and lessen Islamabad Political leverage on it.
Secondly India is desparate to have trade with Afghanistan and as you said to reach CARs BUT its a wishfull dream that India will get any levearge just because US Is in Afghanistan and India has "good" diplomatic ties with US.
Plus the Iranian Port which you mentioned and got over the moon for that, well till the time US is in Afghanistan she will never ever allow Iran to get advantage and have booming trade using Chahbahar
and its also unlikely if US will allow just to please India at the cost of empowering Iran.
Don't worry about US pressure on Iran, Iran has many sources to payback the US pressure for that matter, Iran has with this new arrangement, is positioning itself as custodian of new trade route to afganistan, Russian and central asia. Iran has already engaged Russian and India to improve the North-south Corrider that can carry goods from India to southern Iran and therafter across Caspian Sea into Russian and Europe.
On top of that Iran, India and Central Asian republic of Turkemenistan have also singed an agreement to transit goods from Iranian Port of Bandar Abbas to central Asia via Turkeministan. Goods can transfer either by Road or Railway route as Iranian and the central Asian railway system have been inter-connected since mid-nineties.Three sides also found possibilities of finding road access to Tajikistan and Ujbekistan in Cental Asia, in the case their cooperation can result in linking the Chabbar-Dilaram road to Afgansitan.
PLus as i said before Chahbahar is a seasonal Port and can not work in Monsoon season.
Oh Man, Iran has declared Chahabar port as a free trade zone, impact of Monsoon may be there but Iran with the cooperation with India has taken care of those climatic effect. As India has opted for the construction of Port and more then mature enough to remind itself about monsoon effect, so preventive measure may have been already been taken. Required Infrasture at Chabhar port may have already been deployed to fight anykind of cliamtic Catastropic eventualities.
It is not that such climatic change will effect Ultra-Billion Trade surplus of Iran.