Why Indian Client Projects are following ICP implementation for Salary Structure?

Summary:

It's my second india client project & I'm not quite satisfied with how certain things are.

ICP Salary Structure:

1. Create an element say ABC Salary Structure
2. Create inputs values(salary components) like Basic, Monthly CTC, Annual Gross, HRA, NPS, PF, Special allowance, etc.
3. Now write a element input validation formula to handle the salary structure logic such as Basic = 50% Annual, HRA = 20% Basic, etc
4. Create a ICP for the above element.

Cons:
- ICPs are not mandatory. those are meant for non recurring/off-cycle payments.
- when someone's salary is changed, this element has to be changed using HDL.
- difficulty in maintaining the same.