Is it still? Afaik now with everything HTTPS, caching proxies on the ISP end are completely useless.

We instead now see (proprietary?) cache boxes by big players like YouTube and Netflix that ISPs can install in their DCs, but that seems less elegant, even though it gives the content providers much greater control over what, when and how much gets cached. Still, as a smaller fish, without going with cloudflare, there's no caching involved anymore, probably not even if I decide to run my site on HTTP only.