The branch was started in 2011 and still has a long way to go. The placement scenario however seems promising since the first batch itself received the highest offer of INR 10 LPA. Most of the seniors I know who belonged to this branch were dependent on off-campus placements and got placed in SAP Labs.
The reason on-campus placements for Integrated MSc in Math and Computing at BIT Mesra are not very promising is that students for this program aren't selected via JEE Mains. Big companies like Goldman Sachs, Amazon, Walmart Labs, etc don't find these students credible enough to work in their companies. However, recently MnC has become the fastest-growing branch on campus right now with students receiving plentiful internship offers from foreign universities, IIT, and IIM.
Ultimately I would like to comment that go for this branch only if you are genuinely interested in it and not as an escape route to one-year JEE preparation. Don’t go for it just because of placements you will end up being disappointed.