रेलफैनों को आता है ज़िन्दगी का मज़ा लेना

Since you asked for difference, Gist of things.
1. Fully stainless steel body, less weight, lesser stress on the rails.
2. Coupling as you mentioned different (its not exactly same as CBC in ICF)
3. Fiat bogie, different kind of suspension, (LHB coaches have axle mounted suspension system whereas ICF coaches have dashpot type suspension system) reduces the standard oscillation we are so used...
more...

to.
4. Wheel design LHB coaches have a shorter wheel base thus improved ability to negotiate curves at higher speeds.
5. Disc brakes against thread brake system in ICF.
6. LHB coaches requires less maintenance (intermediate hauling every 5 Lac kms, and periodic hauling every 10 Lac kms) whereas an ICF coach has a shorter maintenance schedule (intermediate hauling every 2 Lac kms and periodic hauling every 4 Lac kms)
More in below two links
Quora: click here
More detailed technical information: click here

Here is the answer
1) Can't IR make conventional coaches using stainless steel ?? If yes then what's the use LHB ?
2) Even if coupling is different but it's effect is still the same I.e coaches will not roll over each other in case of a mishap
3)In India as I already told that 90 % tracks aren't even properly 110 fit so...
more...

oscillation and all that is not something to worry about when train is running at just 100 kmph..LHBs should be used in train having MPS of 130 or above.
4)Even with LHB coaches trains are running at the same average speed as it ran with ICF coaches so that means that atcurves even LHB trains slow down.and the difference will be just that ICF train will run at a curve suppose at 40 kmph then LHB can do it at 50 kmph and as there is no tilting mechanism so speed at curves willnt affect the average speed of train by even a minute.
5)at a speed less than 110 kmph even conventional braking mechanism is efficient
6)that's right but still keeping the cost of LHBs in mind I will say that for an in debt organisation like IR it's better to use cheapaer technology..

"Can't IR make conventional coaches using stainless steel ?? If yes then what's the use LHB ?"
The moment you are going to alter current ICF and manufacture stainless steel ICF the cost is going to any way increase, so your whole argument fall short there. Cost of LHB is not there because of the name LHB, its because of the input raw materials.
Have a simple question, for argument sake. just because your parents have to borrow money to educate you as well as make ends meet does that mean...
more...

they should have to provide you substandard education or no education and give you unhygenic food ? instead of providing you good food and education ?