Categories enabled normally wouldn’t send an email directly to the Trash folder. That’s only automatically detecting the type of email and showing them in different Category Inbox tabs.
See extract below from the eM Client V10 Blog.
https://www.emclient.com/blog/em-client-10-has-been-released-687
Customizable email classification into Inbox Categories
eM Client now supports category tabs in your Inbox, so you can have the most important messages at the ready while the newsletters, social site updates, and other emails are categorized into separate sections for your convenience.
There are several options: use just two categories (Primary and Other), Google style model (Primary, Promotions, Social, …), add or remove other options (All, Updates, Forums, Other, …), and mix and match based on your preference.
For Gmail accounts, categories are synchronized from the server while eM Client uses its own algorithm to sort messages for other accounts.
If the default categorization does not fit your preference, drag the message into a different category tab or change the category via right-click on the message > Category and assigning the right one for you! You can also merge different categories together, if you perhaps want to see your Social updates in your Primary inbox.
Together with this option come Custom rules for category organization – when moving a message, it is possible to set any new messages from the same sender to go into the same category and you can also move all older messages into this category.
Custom rules and all category settings can be modified or removed in Menu > Settings > Mail > Categories section.