In ideal world, payslip is not required and everyone get hired at fair salary. But also in ideal world, every hired employee works perfectly up to their potential and expectation that was perceived during interview.
Sad to say because humans are imperfect, so sometimes rules need to be put in place, HR is just one of many protection mechanism. I sometimes call this traffic light. Nobody likes it, but we all know what happen to human behaviour at busy junction when traffic lights fail..
As employer and manager, you can always see fair share of those who ace the interview, peer reviews and get very high salary. But the expectation not always up to par. We call this interview expert, built solid career and high salary just on being good at interviews. LOL. I am sure we all know someone at some point in time who fit this description.
The problem then is most company will find it almost impossible to reduce salary and time consuming to do termination of employee who is below expectation in reality.
And human also tend to always imagine own salary should increase over time. But what if in reality fair market value is actually lower? Would one then still accept the job, if truly were looking to be paid fair market value? Or stay in current job and put hand up to volunteer pay cut?
Anyway, just sharing. Some company ask for payslip, some don't. If they ask, I have usually provide. Over the years have also signed all sorts from PDPA, NDA, consent to investigate personal info, non-compete clause, etc. Standard process for some companies.
Up to us to decide if we can live with the requirement, if not, then there are many companies out there that don't require such. And there will always be someone else who will take the job if we don't want. Life goes on for both sides, don't need to feel stressed or unfairly treated about it.