Yes coz if you just give him money first, then he can just run away with it and refuse to transfer the title. I also just bought a car for my son which I paid cash in full. My process was as follows:
1. After cross checking the car and the title, I bargain until we agree on the price.
2. I checked on any outstanding summons and inform the owner that she needs to settle those.
3. I paid a deposit of rm500 and get a receipt. I also asked for a copy of the owner IC, name card, and can also ask for full address if you did not go to the owner house when checking the car.
4. The owner arranged to pass puspakom inspection and settle all summons on her own cost. Puspakom inspection MUST be the seller responsibility because that is to ensure that the car is road worthy and sellable to begin with! So it's the seller responsibility to get it up to road worthy condition so it can be sold otherwise they cannot sell the car to begin with.
5. I checked online to ensure all summons settled.
6. I went to my bank to prepare a bank draft for the remaining balance of the price.
7. We met up around 8am at JPJ Wangsa Maju to do title transfer which she paid as well (around rm200 if not mistaken). So once I got the title, I gave her the bank draft and I took the car immediately, finish. This last step was done in less than 30 mins.

Well lucky you then. Maybe buyer felt very comfortable with your selling price already so don't mind settling everything else. Or maybe buyer is actually a used car dealer/agent? For me, at least the puspakom should be seller's responsibility because without it by right seller cannot sell the car. Title transfer fee can be negotiable.

Well technically or legally the summons are for the previous owner and not the new owner and I know there are a lot of people who just buy car with still outstanding summons and have no issues yet with them, BUT you still would like to have a clean car right? If somehow suddenly the car got blacklisted, you don't want the hassle to clear it up right? So IMHO you should insist to the seller to clean up the outstanding summons attached to that car/license plate just to be on the safe side.

With things that may involve money and police, better be safe than sorry.