No, you are wrong actually I have read ans related to this one person(actuary) said that they calculate IBNR for life insurance contracts but they didn’t use run off triangle.
And according to other one, Run off triangle technique can be used to calculate IBNYR for life products but not IBNER that is, development in frequency can be estimated but not severity. Even for aggregate triangle- no need to solve when we can multiply with an estimate of unreported incurred frequency. Even for regular payment benefit- uncertainty is for how much time insurer will pay rather than how much. For Bonus cover- the amount would be applicable on the incurred date, still no uncertainty on average payment per accident year.( different traingle needed for each homogenous group)
Conclusion, I’m getting that we can use it but it becomes more hactic.
Now I got this!!