Is it better to start off as a Freelancer or register as a business?

Depend on how much after hour mental load you can carry and how far you project the business to be

If you looking into far and beyond, I will say that register as a business almost always win.

Why? It give some assurance that your work is better and the impression that people get from pte ltd versus freelancer are very different. You may disagree but do that after you talk to more small business owners / SME.... Not a requirement but might have some slight bias.

The other thing is about accountability which other answers had shed some light and you can google for more info as well.

Lastly to network and joining events as a company's representative is always better in most ways even though you are the only 1 in the company!

Additional Info:

Payments - Nowadays can pay to business reg number via PayNow and others, no worries

Networking - Covered above

Legal - There are some business template which you can use online. You can engage a lawyer for 1 time to go thru' the contract. Since you are going to SME or small entitiy you can draft something at your end and let them sign your version of contract rather than theirs. I propose to keep each contract as short as possible, say 1-3 months and have many contracts. Let's say you and your client want to work for a year, sign a MOU instead and have contracts signed every quarterly. This would reduce some risk that at your end and it is only possible for small companies to accept such terms and not bigger companies.