Exactly, the dollar symbol being used for different currencies is freaking confusing. We are on the internet in cyberspace, I usually use a VPN with location in Canada and don't even remember. Then I see prices in Canadian dollars thinking they are US dollar and the same with the Mexican Peso.
Valid argument why it's bad to use $ for same currencies. But that's just because the context is not clear in the cases you mentioned.
Do you think Lightning will be here in 100 years or new protocols and technologies will arise? You can also send SATs through Liquid without Lightning.
Yes I think so. But the difference is that in both these contexts, '⚡100' will be clear: To send sats. The number is sufficient, no? And a number will always be part of paying for something since you need to know how much you need to pay.