Hi Julian! Welcome to the forums!
Yes, you can view the images directly from the Epson since it will act like an external hard drive when connected. However, in order to do this, you would have to import them into your catalog like any other set of images. Here's where the problem comes in.
LR will now think of those images as being on that drive. So, whenever it isn't connected you will still see the thumbnails but won't be able to do any adjustments. Also, since the main purpose of the Epson is as a temporary storage/backup device when shooting in the field, you may want to first copy the images to another hard drive (or tell LR to copy them during import). This way the image files are in a more permanent location. In short, I wouldn't rely on the Epson as an ongoing storage device.