Is it good to add the terminal illness rider and other riders to the term insurance plan, or is it better to keep term insurance separate and have another insurance for terminal illness, permanent disability, and other needs?
Riders are good, meaningful, and cheaper as they have a very insignificant additional cost. It comes in convenient if something happens to you, for example, a critical illness rider. Most of the time, the payoff of insurance is when you die. But here, you have a meaningful payoff from insurance when you don't die but are faced with a crisis or with misfortune, and in such circumstances, this insurance money helps very aptly.
So I think opt for such riders as add-ons to your term insurance.