In the end, it’s up to your usage.
If you only have one iDevice, rarely use apps, and hardly take any photos, the free iCloud tier might be enough.
For me, I have an iPhone, two iPads, and Macs as well. I use iCloud photo and for backup of all my iDevices. Plus I take a lot of photos and apps. My WhatsApp backup alone is already a few GBs. 99c a month for 50GB iCloud is a no brainer for me. The 200GB tier makes sense if you have a partner or family as you can just share the storage with other family members.