Maybe it's a nice way to quickly test a new service or change over the internet without going through the git process, same way one would use ngrok - I could see that being helpful when prototyping / pocs, etc - before deploying changes to your app via the proper channel, especially if you are already using cloudflare for your domains/apps. As other people said, it probably would not be practical or scalable for most people to run an app 24/7 from their laptop using their home or office internet connection.
My initial thought was desktops generally run 24/7, with laptops running when in use. At least for the customer at the market intersection for this type of product.
I often tell my dev colleagues to avoid having their PC turned on all the time, be it because of the electricity bill cost, environmental impact or simply to make the longevity of the hardware a little longer. Granted almost everyone just ignores those things even if they're conscious of it, so I'd say you're right
There's pros and cons on the longevity side. 24/7 use causes more wear to mechanical parts (fans for instance) but can be better for the electronics, as heat cycles are a big part of the problem there.
Yeah my desktop is on 24/7. Laptop is on when in use. Phone is on all the time too, of course, but I don't use it for browsing or work nearly as much as my desktop.