But it's not just for personal information.
HTTPS keeps your ISP, your wifi hotspot, a dodgy router, or anything else from injecting ads and tracking information into your pages
HTTPS ensures that the server and information the user is requesting actually comes from you (and not a shady middleman who might give out bad information or just annoy the user with a slightly broken setup)
HTTPS ensures that content isn't being blocked by a bad government actor based on it's content
HTTPS keeps bad actors from injecting malware into your javascript, your images, even downloaded executables (there is "one click" software out there to inject malware into any .exe download it can find on the network in real time)
HTTPS helps protect against "dragnet surveillance". That doesn't just include bad governments, but also an ISP which might build a profile on you based on your browsing habits.
HTTPS treats information as "secure by default". You won't always know what is and isn't "private" to each person. "phrasegenerator.com" might just be a fun game to you, but to someone else it might generate a phrase that could get someone fired, or worse, based on the content of that phrase.
And using HTTPS everywhere means that it's harder to identify "secure" information from "insecure" information. Breaking one HTTPS connection one time for one person and one server isn't "easy", but it's not impossible. Breaking HTTPS for all connections to everyone every time for every server becomes practically impossible.
The overhead is next to nothing, the complexity mostly abstracted away, and with stuff like Let's Encrypt the "maintenance factor" is quickly getting reduced to "fire and forget".
There's no excuse to not use HTTPS any more in my opinion.