Increasing the maximum file upload size in WordPress is not necessarily a bad practice in itself, but it can have some potential downsides that should be considered before making any changes. Here are some reasons why increasing the maximum file upload size in WordPress might be considered a bad practice:

Security risks: Allowing larger files to be uploaded to your WordPress site can increase the risk of security vulnerabilities. For example, larger files can take longer to upload, which may increase the likelihood of timeouts or other issues that could be exploited by attackers.
Performance issues: Large files can also impact the performance of your website. Uploading large files can take up valuable server resources, which can slow down your site or cause other performance issues. In addition, large files can take longer to load, which can lead to a slower user experience for your visitors.
Storage limitations: Increasing the maximum file upload size can also lead to storage limitations on your server. If you allow users to upload large files, you may need to allocate more storage space to accommodate them. This can be costly, especially if your website receives a lot of uploads.
Compatibility issues: Increasing the maximum file upload size can also lead to compatibility issues with your WordPress plugins and themes. Some plugins or themes may not be designed to handle large files, which can cause errors or other issues.

Overall, increasing the maximum file upload size in WordPress should be done with caution and after careful consideration of the potential risks and downsides. It may be better to use alternative methods, such as third-party file hosting services, to handle large files instead.