No... but just for editing and office tasks it's great. For Final color grading of a serious project like a film I would still recommend a properly calibrated monitor
Not everyone has an iPad or a Macbook. And you have to buy an iPad Pro to have a 13" secondary display. The expense is very high in that. For this purpose I bought a an iPad Air 11". It is usable as second screen, but it will never be big enough. Besides Apple decided to drastically reduce its usability by forbidding you from commanding the second screen with the touch of the fingers. You can only interact with it, using the mouse arrow or the Apple Pencil. And this is very limiting. There are third party apps that allows touch, but they're much slower than the macOS integrated solution.
I used to use an ipad with the Mac so you definitely can. I showed that in my video about the Macbook Air 13. However that doesn't work with a PC and also there are some limitation when using an ipad. Not to mention that an ipad is a lot more expensive than this monitor. This monitor can also be used with a PC, media players, game consoles etc. If you already have a Macbook and an iPad and the limitations don't hinder your workflow then definitely there is no need to buy new gear like this monitor.