Problem, Strike requires KYC regulations. You would have to awkwardly enter your details in or the other person's. A better idea might be to install a good, reputable wallet app and then send Bitcoin on-chain or via lightning to that person.
In regards to the coffee thing, well... Lemme introduce you to Bitrefill and thebitcoincompany. You can go to either website or app and buy gift cards with Bitcoin on-chain or with Lightning. And yes, they have Starbucks gift cards. As long as they can add gift cards to Apple pay or Google's wallet app, then all that's left is to try tap to pay (NFC) at a local POS device.
Alternatively they could use a credit card to buy the coffee and then pay off the bill with Strike's bill pay. But that's only if you can get past the awkward part of putting in your info or someone else's.