Yes it's fun, but there is something more fulfilling and tangible - the unique characters that some of these old wonders wove into the images that make them so enticing and attractive to look at. They provide an alternative to the modern, sharp, contrasty, and highly corrected images that look perfect, but lack characters. Many very old lenses are usually full of "faults" of one kind or the other. They vignette badly, they flare like crazy, they have low contrast, they may have horrendous distortion, they have bokeh so horrible that make your skin crawl, and so on. Well, is your partner perfect? Do you want a partner that looks/acts the same as everyone else? We like our partners because they have characters and traits that stand out from others.
So yes. It's worth the time to make those odd-ball lenses usable on the digital cameras; to endure the disgusted look of some people looking at my ugly Franken Lenses. Because we love our old lenses and the kind of pictures that they can create.
Sailboat - NEX-6 & AM [Ross Xpress] 5 inch f4 @ f5.6.