I am still missing why people are so crazy about airdrop. Sure, it seems nice, and is nice to interact with, but all my stuff is already in the cloud and i don't seem to need to share it very often with people around me. What are some of the use-cases you personally use airdrop for?
But neither of these implementations are going to provide this functionality, because of lack of development kits, right? So in the end people would just send it over some messaging app, which scales nicer, or create a shared album, which also scales nicer. Because smashing phones in group of 10 people might get tedious.
The functionality described by the person you are replying to is part of all Apple devices. It also works without being on the same messengig app and without having the recipient in your contacts in the first place.
Another example for AirDrop use cases is transferring large media files to another device. People use that all the time for moving recordings to their editing computer, for example. Even if you have all your stuff in the cloud (which not everyone does) - it‘s much faster to do a local transfer than uploading and downloading something like a high res raw video from a modern phone.
You don’t need to implement airdrop as separate functionality.
If you are capable of sharing a resource in a message or album, it is also automatically shareable via airdrop. iOS treats them all the same via the share sheet.