You can actually keep it offline (permanently) and their sync is more immediate. iCloud gave me issues when downloading many (large files) and you couldn't really prioritise certain files. That, and a few other smaller things - like a much better web app experience, etc.

I actually still pay for iCloud - but mainly for the Photos storage space.

I pay for both.

iCloud for photos and Mac backup.

Dropbox for files. iCloud is somehow not good for low latency file syncs.

Even for photos it’s not excellent. It takes a while for photos on my phone to show up on my macOS Photos app. But I’m less sensitive to photos lagging than actual files lagging.

Dropbox is instantaneous.