Frames was developed for off-line applications. It provides a flexible platform that allows a variety of functions to be applied to a single page (screen). It is not a good choice for internet use because, among other things, it is not friendly to search engines that must locate a single internet address.
A no frames web page is like a painting. Everything is applied to one canvas. All the elements of the page are coded to render as a single unit. Everything on the page has the same address.
A frames page is like a collage. The page being viewed is actually blank. It only provides a place for a mosaic of other web pages, each coded separately, to be displayed. The coding for the viewed page tells each individual page element where to appear and each element has its own address.
Restricted browsers like cell phone browsers and the WebTV browser must often reformat a page to allow it to render in the space available. It's easier to reformat a no frames page as only one source code needs to be altered.