I said it before but repeating  - as I understand the base layer would be used for large transactions because fees will be prohibitive for average person  - means transactions between corporations or nation states would be on base layer . Why would you want them private ?  They should be mandatory in public eye .. 

As for buying coffee and pledging #Sats to open source  - I guess #lightning is already private - could be more !

That said  - I guess Satoshi's knew it well   !  Who is better advocate of privacy than the one absolutely "unknown"  ..