What is the primary benefit of using web-based email services like Gmail or Outlook?

The primary benefit of using web-based email services, such as Gmail or Outlook, is their easy accessibility via the internet. These services are designed to be accessed from any device with an internet connection, allowing users to read and send email from virtually anywhere without needing to install software or maintain servers. This flexibility is particularly valuable in today's mobile and remote work environments, where users may switch between devices like laptops, tablets, and smartphones.

Although offline accessibility is a feature offered by some web-based email services, the primary characteristic that sets them apart is the ability to connect and use the service seamlessly from any location at any time. Cost-effectiveness may apply to some services, especially if they offer free tiers, but it's not the defining feature of web-based email. Similarly, while custom domain support is important for businesses, individual users typically prioritize convenience and the ability to easily access their email, making internet accessibility the most significant advantage.