To be clear: this is a bug, not a feature request. The screen for adding a wallet very clearly says that an address or key can be used.
Because keys aren’t working, users have to manually add EVERY individual address, which is a huge pain not just because of the immediate hassle of adding them one by one, but also because it complicates record-keeping whenever ADA is transferred from that wallet to another wallet (e.g. transferring to an exchange).
Please make fixing this a priority! I’m very happy with Koinly except for this longstanding issue!