DIY may be unpolished and unprofessional. With an established business that doesn't already have a website, DIY is probably the wrong choice as the wrong decisions could negatively impact your business. On the other hand a newly established business with untested premises and a limited budget DIY is probably the correct choice.

Choosing the correct DIY platform: Website builder or Wordpress

What is the best ROI on your time? Is it in DIY your website or is it spent serving your clients and building yoru business. There's a lot that the DIY person may not be aware of that goes on behind the scenes including UX, SEO and technical issues that are easily misunderstood or skipped entirely. As a website novice the DIYer doesn't know what they don't know.

Hosted platforms such as Wix or Squarespace will take care of security. Self hosted such as wordpress you are responsible for security update.