If you have to upload multiple files manually, it requires more clicks than seems to be necessary.
First you have to click on "Edit Import", then select the right tab and only then you are able to drag your file to the page. At this point, you cannot see the name of the import slot, so you have to remember correctly which import slot you opened. No problem if there is one import slot, but if you have to upload 5 files into 5 import slots this process is a bit cumbersome. It also feels somewhat counterintuitive to select "Edit import" if you only want to import a file, you do not want to make actual changes to the settings of the import slot. Especially for users who just need to upload files and who do not need to have extensive knowledge about how to set up an import, this is easier and also safer, as they do not have to go into the editing part of the import slot.
To make this easier it would be nice to have a box to drag your file already at the overview screen of the imports: