I use it these days. I was using OnOne Photo Raw on my MacBook but when I upgraded to the Mac Mini M2 PR kept running out of memory. Not surprising, perhaps, as the MacBook has 32GB while the Mini M2 has 16GB.
So, anyway, I set mine up so that the photos are imported into Lightroom Classic on the Mac Mini, I select some photos to edit which are synced to the iPad (Air 5), I edit them on the iPad and the changes are synced back to Classic, where I take care of DAM, metadata, titling and captioning, and so on.
But to answer your question, I think it's well worth the £8.89 or whatever it is per month just to get all the extra features. But, of course, this is on the iPad Air 5 with an M1 chip and 8GB of RAM. It might suffer on a regular iPad. I should also add that you can have free portfolio websites, which could on their own be worth that price a month to some people.