We knew it wasn't comparable to noncustodial lightning, but I assumed that Spark customers would retain the privacy of a custodial service. That is, I thought Spark would know about balances and transactions - not anyone curious enough to look. This is akin to Coinbase giving each customer a bitcoin address and forcing reuse.

So bottom line what we're saying is that `spark negates lightning privacy benefits` - but we already knew that it wasn't comparable, right?

optimism

In addition to @benthecarman's tool, there's also this

https://lightningdecoder.com/

Scoresby

lightning

Does Wallet of Satoshi make all users balances public via Spark?

Eh there's not much difference between calling something like `decodeSparkPaymentRequest` and `decodePaymentRequest`. 

If someone in possession of one of your bolt11s wants to know your balance and transactions, they won't need new skills to do it - just the right tool.