Email security: what is the actual risk level of sending one's govt ID as an email attachment?

It’s not a state ID, rather my state-issued patient ID for medical marijuana. Only one dispensary is offering delivery to my address and they will deliver only if you’re willing to email front and back images of your patient ID to them.

I told them this isn’t secure and they said it’s the only way they’re able to do it. I know that means it’s the only way they’re willing to do it. But how can I work with this? Is there a secure service I might use that would result specifically in what they require (an email arriving to them with the two pics)?

(To be clear I only care about info security – I have no need to keep it secret from anyone that I’m a MMJ user – and my patient ID doesn’t show my driver’s license info, just my photo and patient info.)