Being a custodial system is not such a big problem.The problem is that they are lying about their true intentions and try to present Spark as a L2, when in fact IS NOT. If they would just say what really is and stop pretending to "save Bitcoin" will not a problem at all. Who wants to use their shity crap network, fine. But don't lie that is bitcoin. People should read this article entirely and realize that what I am talking all days is true and is a big warning:

Unlimited Hangout

The Chain Of Command: How Facebook's Libra, Bank Regulators, and PayPal Built A New World Currency

Two companies closely tied to Peter Thiel – PayPal and Facebook – have embarked on apparently unsuccessful efforts to create a “new world cur...

Spark is a real threat to Bitcoin !