Resolution and apps in Ipad Mini display

Another section unclean for me:

"because the screen real estate is so much larger than an iPhone but icons are now roughly iPhone size, apps with lots of navigational elements can be a little less intuitive to navigate. Furthermore, the keyboard size feels altered — most notably in portrait — and the keys don't seem tall enough for my fingers. On the other hand, the mini makes landscape typing a lot easier"

Could you explain and synthetize the question and the problem the apps have on this display?

Thanks very well!