If you have different keys per app, then you can keep notifications about those things in those apps, which is a win. 

However, the issue are DMs. If you are using a different key in each app, the DMs will be different between your apps. And people might confuse your keys, sending DMs from their Olas account to your Amethyst account, instead of your Olas account. It will be messy.

But otherwise, you can already use multiple keys today.