Important distinction between transaction number and transaction volume. Say someone makes 100 transactions/month, totalling 10m sats, maybe 95 of them are on a custodial lightning wallet, and 5 are lightning or on-chain self-custody transactions. However, those 95 custodial transactions might only have been for 100k sats, and the sovereign transactions were 9.9m sats.

"Usage" needs to be further explored.