paramilitaries have been created because they are cheaper.
instead how about, creating a brigade sizes rapid action contingent with in ITBP, train these chaps on par with IA. so that they can hold fort till IA comes in.
First of all. the post you quoted is not (Not) the role of ITBP but tasks of ITBP. The role of ITBP is the management of LAC along the India China border.
Secondly, they are not Paramilitary they are simply armed police called CAPF.
Thirdly, they are not cheap at all. The cost of maintaining one battalion CAPF is many-fold than the cost of an Infantry battalion. Their Pay. perks and allowances are much better than Army. Most of them are of Bahdur Singh Yadav type who make videos of patali Dal and send those to the PM.
Fourthly, from their recruitment days itself they are never taught to undertake any offensive operations. They are unfit for that task. It would not be fair to ask a 50 year old constable to go and attack and held of them are at 50 plus farting around on posts.
There were even proposals to transfer ITBP personnel of age above 45 to transfer to other CAPFs but the same does not seem to get implemented..
So this force is only a social justice employment scheme...