If you want to be taken seriously online, having a website with your own domain can help. Your own domain helps you build your brand and gain your visitors' trust. Internet users know exactly what to expect when they click on your site. In the long run, they will associate the domain name with your content and what you offer. A website with your own domain can make your brand much more recognisable.
It makes sense to get an email address to go with your own domain. When communicating in a professional setting, it's a good idea to use a personalised email address. If your website and email address have the same domain, this makes a great impression on customers and business partners.
Having a website with your own domain also helps with SEO because search engines like Google and Bing are more likely to rank a website higher in the search results if it has its own domain. This in turn leads to more visitors coming to your website.