Guys I am redacting this post as I have been asked by the bank for non disclosure as mentioned in TnCs else my account would be suspended. They had asked me to remove this as this violates the TnC related to not getting reward points for CC payments.
Digi gold and visa platinum are almost useless if you have signature/MC world.
If you get option on app to apply from Signature, apply it. Else you can call cc and ask them. Sometimes a fool would pick up call and tell you that only one card can be issued, tell them to connect to a senior agent and raise request.
Also, since you have HDFC visa plat too along with indus MC world, I guess you are sorted out for about 1.6lakh bill payment.