Apple Introduced Swift in 2014 at WWDC and it has really taken off. Not to say it’s necessary to use for Apple Apps. There are just many reasons to use it. Swift is changing everyday which can at times be frustrating when using older code , but there are ways to overcome the challenges. It’s the current language that many support and I believe will continue. In most cases Swift has streamlined the syntax as compare to Object-C. So, that’s why I use and support it.
Apple’s Developer Site for More on Swift.