I considered…for what for me was a pretty long time…doing that but found that after analysis it wasn’t a good idea when I considered it. We used to live in an RV full time and hence had limited internet both speed wise and bandwidth wise…so that was the first nonstarter for me. Second…I have an Adobe Photography plan subscription which gives me full Lightroom and Photoshop on the Mac as well as the ability to use the Lightroom Cloud version. What I found out after taking a look at the cloud version is that it is way less sophisticated than the real Lightroom is in addition to the fact that you need fast, basically unlimited ethernet to use it as iPad storage is limited.
If you are happy with what Photos on the Mac does as far as post processing goes then perhaps the limited cloud version of Lightroom would be sufficient…but for anything serious amateur and up I believe it is too limiting. There is limited (perhaps none) ability to use plugins, passing images off to side apps like Luminar, HDR apps, or ON1 is harder and the results are not directly integrated back into Lightroom.
We moved back into a sticks and bricks house in January and no longer live full time in the RV…so the speed/bandwidth issue went away for me…but even after reconsidering the online version it is still way too limiting.
I’m still using my 2015 rMBP at this point… but most of it’s keys have no letters on them any longer and it’s getting pretty long in the tooth so it’s up for replacement before we start the international travels portion of our retirement after the corona crisis is past. I will either get the new 16 inch MBP or the fully loaded 2020 MBA…each has their advantages. The MBP is obviously way faster than my old MBP…but it’s also heavier and more to travel around with and my laptop and cameras will rarely (if ever) not be on my person as we travel about the world so lighter is always better, particularly as I’ll have my Nikon DSLR, probably 3 lenses total but perhaps only 2 for some trips and perhaps 4 for others depending on whether I need the super telephoto for wildlife, power supplies for everything, a couple of portable drives to back up photos on, iPads and iPhones, etc. Looking at the new MBA…a maxed out i7 one will be about the same performance as my old rMBP…and I can live with that to save the weight I believe. There’s also the 1500 or so bucks I’ll save with the MBA but that’s a lower priority than weight and performance to me. Anyway…now that I’m back in a house with more space I can always keep the LR catalog and photos on an external drive and plug it into the iMac 27 I bought for the office when I’m here…and if I get super lazy I can run LR on the iMac via Screens from the laptop on the lanai.
Long story short…the iPad only would be acceptable only if you plan on always having fast/unlimited internet and if you’re satisfied with the limited capabilities of the cloud version of LR and Photoshop in then iPad.