For personal use, requiring login is fine, but if I wanted to share it publicly then it would need to use the read key. Many (all?) of built-in emoncms apps use read keys.
Given that I’m already sharing via MyHeatPump app, it’s not hugely important to me to be able to share the MMSP app. Probably only useful for comparing two MMSP systems.
Some people may have privacy concerns about sharing live data publicly, so the addition of a “delayed” option could be useful, as @TrystanLea suggested in his opening post on Sharing heat pump data.