Creating a web page that stands out for its professionalism requires both knowledge of the syntax and artistic sense at the best of times, but designers generally have an easy time producing quality work for various clients once they have acquired the necessary experience. This is because there are not necessarily many distinct web browsers that the designer has to take into account when crafting their page's structure, and the mainstream browsers are largely capable of fully executing the same pages without issue. Since virtually everyone uses the same few browsers, there is much less of a chance that whatever HTML, CSS, and JavaScript syntax the designer has prepared for a given web page will fail to work flawlessly for a given reader.
In contrast, emails represent a far more treacherous and vaguely defined environment for someone to create reliable HTML-based designs within because there are many more email clients in common use. Unlike with mainstream browsers, seemingly every email client has its own partially incomplete approach to parsing emails that are structured like web pages. Designers who are tasked with creating HTML email templates that get sent out to various websites' customers whenever they place orders essentially have to work with outdated code to ensure that all email clients can physically display the template without errors.
For example, since various email services will not recognize all facets of modern CSS-driven styling, email templates should not be using anything more complex than the antiquated "bgcolor" parameter to set flat background colors for sections of the email enclosed in "div" tags. An embedded image that essentially recreates a potentially complex web page would only actually display for a fraction of those receiving the email because various security and privacy systems would be set up to prevent images in emails from being automatically loaded. As a result, the designer has to come up with an email design that will be legible to readers even when images are suppressed. Finally, enclosing the email's contents in a rudimentary "table" HTML tag is the only universally reliable way of aligning the contents toward the center. For more information click here https://lune.co/post/how-it-feels-to-code-an-html-email-template-in-2021.