Honestly, I think iCloud+ is worth it if you use your iPhone a lot. The free 5GB runs out almost instantly once you start backing up photos, apps, and messages. With iCloud+ you get more storage, plus handy extras like Private Relay for privacy, Hide My Email, and the option to share storage with family.
For me, the main benefit is just peace of mind knowing my photos and phone are backed up automatically without me having to think about it. The cheapest plan is under £1 a month, so it’s not a big cost either.
If you don’t take loads of photos or don’t care about backups, you could probably skip it. But for most iPhone users, it’s honestly worth having.