My 2011 and 2013 iPads get turned on about every 2 years, just to see if they still work. They are too slow and clumsy to do any work on, and they are too heavy to read in bed with (hurts my body). I have zero reason to share photos with them.
I have no iPhone, so shooting a picture on my iPhone is Not A Thing. Pictures I shoot on my Android phone are uploaded automatically to Google Photos.
My sister is the only person who uses iMessage with me. I typically discover the message about 5 months later on my desktop.
I have an Apple laptop and two iMac. I have a lot more than 5 Gb of photos -- 5 Gb being the storage size for iCloud unless you pay extra. I already have a 2 terabyte Google Drive; I can't think of any good reason to pay Apple a very similar amount of money to share photos in my residence. If I want to share photos in my residence I can just create a public share.
I looked through all of the "Applications using iCloud" that can be enabled. Apple Maps? Almost never use it, and what even would there be to share? I guess some people might find it handy to plan a route on a desktop / laptop and then use it for driving directions on their iPhone... but for what little navigation I do, it is easy enough to just type in my destination address in Google Maps on my android phone.
The only application I saw on the list that might be useful for me would be sharing my keychain between my different Macs. However, that requires turning on Two Factor Authentication. 2FA can turn into a circular firing squad. When my housemate misplaced their iPhone last year, they couldn't log in to their laptops because the laptops were all set to 2FA to their iPhone, and the bypass procedures all involved authenticating on a different Apple device... each of which in turn was set up for 2FA. (Eventually I dug out an old iPAD whose OS was too old to require 2FA, and was able to use it to authenticate AppleID use to break the chain.)