In 1Password there's at least a half dozen ways that drag and drop could be used:
- Drag a password into a password field
- Drag an attachment from Finder/Explorer into an item
- Drag an item from vault to vault (or collection in Bitwarden parlance)
- Drag an item into a tag or folder to add that item to the folder, or add that tag to the item
- Drag an app to the 1Password icon to create a software license item with the icon of the app as well as name
There are also drag and drop functions, some similar to above, on iOS as well.
Bitwarden is... and I agree with the grand parent here, awful from a UX angle, compared to 1Password. It's certainly functional, but that's about where it ends for me.