I keep seeing these ridiculous non sequitur comparisons of iPads to MacBooks, MacBook Air, or so on. It's silly. You can't buy an Apple Notebook that performs on par with an Apple iPad for the same price or even close. iPad performs amazingly within its domain with ridiculously better battery life. Just try watching an HD movie on your 12" MacBook, that will erase your battery. On iPad? You can watch 3-4 in a row easily.
Yes, Macs are more general purpose. That comes at a heavy overhead cost in performance/battery life. It also comes in at a hefty cost in weight, heat, and total price. The closest you can get in terms of size and weight and heat is the 12" MacBook, anything else is a comparison so outside the boundaries of similarity as to make me question your sanity. If you need something from the MacBook Air or MacBook Pro line that you can't get from iPad, comparison between the two is pointless, you know what you need. If iPad is serving your needs, the only even remotely worthwhile comparison is the 12" MacBook so let's have a look.
First, we know from benchmarks that the performance is roughly equal. But, that's just benchmarks. With optimized software, the UX is much better on iPad. The browsing performance, for example, is WAY more enjoyable on iPad than MacBook. The MacBook is painfully underpowered for an OS X machine, unfortunately. Gaming? Well just play Hearthstone on each at full resolutions, or even downres the MacBook to match iPad. It's barely playable on MacBook, and buttery smooth on iPad. There are also way, way more games on iPad than Mac, with a much higher visual/fun quality ratio than Mac as well. What do you do with your iPad? Anything you can do with it will almost certainly be faster, smoother, and generally better than MacBook.
How about pricing then? To be fair, we'll toss in the smart keyboard although it's not required. You can't buy a cellular enabled Mac, and the highest storage available on iPad Pro is 256gb so we'll compare the Wi-Fi iPad Pro 256 with the MacBook 256gb model. The MacBook will have 8GB of ram because that's the lowest you can get. And you need it. OS X, like any desktop OS, is a RAM hog. 8GB is decent. 16GB would be much more comfortable. Still, we're comparing to iPad with 2GB, which amazingly seems to satisfy pretty much everyone's needs except those who think they need 10 browser tabs or more open all the time without reloading, I suppose. Not an important factor.
So what is the price difference? The MacBook weighs in at $1,299 while the iPad Pro is $899 + $150 for the smart keyboard. So the MacBook is $250 more, performs worse on nearly every typical activity they can both do, can not be used without the keyboard, has no touch interface, can not use the Apple Pencil, could not be purchased in a cellular enabled model, has garbage graphics chip, a barely passable Intel CPU, weighs over double the iPad's weight (more similar when the keyboard is accounted for but, again, that's an optional accessory) and most people, though not myself, hate the keyboard on the MacBook.
Again, all of this depends on what you're doing. But, if you can do whatever it is you want to do with your larger screen portable device on an iPad, you're going to get a better machine at a better price.
Frankly, the iPad is a bargain for what it can do when you stop whining and start looking at all of the massive progress the platform has made despite Apple moving slowly in the "pro" aspect of things. The whole Workflows, scripting, productivity arena of apps has made an enormous difference. Yes, you need to know how to use software on a computer and finding exactly your one do-everything app is less likely, but, so what? That is not the ideal way of computing anyway. Modular, interoperable, smaller components tied together gives more flexibility and that's how things are building out on iPad.
Anyway, the main point here is that if the iPad can do what you need, the claims of its value being bad compared to a Mac are utterly specious. Only someone incapable of basic comparison and arithmetic can come to another conclusion.