Under the heading "Feature that would make my Evernote life better..." There should be a Preference setting to control two behaviors when adding an Attachment to a Note from the Finder.
1. "Always send original file to the Trash?" When a macOS file is added to a Note, make it a default behavior to send the original file to the macOS Trash. Can't tell you how many hours I've spent doing this manually.
2. "Always add <Tag> when adding an Attachment from the Finder." Adding a standard, user-defined Tag to a Note when attaching a file will make it easier to locate Notes with macOS File Attachments created by the user. The user might make the value of <Tag> a file Type, like "Photo," or more generic like "macOS Doc." Currently, the Search tool can find all Notes with Attachments, but cannot filter down to the ones the user attached manually by dragging from a Finder window or using "Attach Files..." menu command.
Being explicit about what happens to a file when it's attached to a Note will reduce confusion about where a file is actually stored and how to find it later. Right now, it's not clear—did the file get moved to Evernote when I attached it, or not? Are there two files or just one?