Yes, the PGDBA courses offered by IIT, ISI, and IIM are definitely worth the investment. You get to have the best of the 3 Institutes:
ISI: It’s rigorous statistics
IIT: Machine learning and CS courses
IIM: Management (mainly finance)
The combination of all three will not go in vain. Apart from these other benefits you will be getting are
Guidance from the best professors in India
Study with people from diverse backgrounds
Experience the culture and academic style of 3 institutes
Such a diverse experience shall make you open to multiple perspectives. You can see your role in society and how you can mold yourself for the better to contribute the most to it.
As far as the placements are concerned, you can voice your preferences. All the 3 institutes offer the best job prospects and placement opportunities and that is something you should not worry about.
In the end, it all depends on your own hard work and determination whether you are willing to avail the opportunities that lie in front of you.