Hi Lynn Towle
Thanks for being an Intune customer and for sharing your feedback.
To clarify, if you already have sufficient M365 E5 or EMS/Intune user licenses to cover all your self-deploying devices, you may not need additional device-only SKU. This device license is useful when customers have, say, 100 kiosks that are not going to be associated with users but they only want to manage the device itself from Intune. If these kiosks will not have user-identity or apps such as Office 365 on them, some customers may save costs by choosing device-only subscription for these 100 kiosks instead of extending their full M365/ EMS. As mentioned above, if you do have user-association (i.e. AAD users login/ logout) on the devices, even if they are shared, then you still require the M365 or EMS/Intune licenses.
Hope this helps. Please feel free to contact your account representative if you have more questions, and we'll be happy to address them.
regards
Mayunk
Microsoft