This wallet is intended for developers to debug their dApps.
A common issue with dApps is that users report that a certain functionality doesn't work for them. It is often cumbersome to reproduce this in a development environment because the dev team doesn't have access to the account. The Debug Wallet can help debug those cases.
With the "watch-only" feature in the Debug Wallet it is possible to connect to any dApp using any tz account. The dApp can then be viewed from the eyes of that user and operations can be debugged with ease.
It is possible to pair any Beacon-compatible wallet to the Debug Wallet. If you do that, the Debug Wallet acts as a "relay" between the dApp and the actual wallet. Requests and responses will be relayed, but the details can be inspected.