Can I share files from cold storage with clients or family?

Yes, but with one important catch: cold storage share links are temporary and expire after 72 hours. So you can absolutely send someone a link to a batch of archived photos, but it's not a permanent delivery link — after three days it stops working and you'd generate a fresh one. For quick "here are those files from last year" moments it's perfect; for ongoing delivery to guests, that's what hot storage albums are for.