Why I sew on vintage sewing machines (VSMs), and some good reasons to consider giving them a try!
Practicality: Good quality VSMs are durable, reliable, and made to standards not possible today. You need no more proof of this than to consider that most sewing machines made 50-75 years ago still work perfectly. You can't ask for a machine more reliable than one that was built to last a lifetime before the days of planned obsolescence. Modern sewing machines simply aren't made to this standard, it wouldn't be cost effective to manufacture them to the same specifications as 50+ years ago. Of course new bells and whistles have been added to modern machines, but the basic stitching mechanics have never been improved upon - in fact the quality has never been surpassed to this day.
Greener choice: We are all conscious of being good stewards of our resources and I can think of no better way to do this than to adopt a solid, metal mechanical sewing machine that will probably last your lifetime. Not only are you keeping an existing machine out of the scrap metal heap, but you are saving one more plastic electronic machine from ending up in a landfill in ten years (or less.) Like any electronic device, a computerized sewing machine will quickly reach the point of no return where it is more expensive to repair it/update it than to replace it. Then off it goes to the dump while you're spending $1000 for a new one.
Cost effective: First of all, you save big bucks on the machine itself. Then, depending on the model you get, the feet and accessories are usually still available at reasonable prices. For example, if you choose a low shank VSM, any inexpensive low shank feet made today will work on it. (However, it will be more challenging if you choose a model with an obscure shank style or clamping system, or very old machines that need special needles or shuttle bobbins.) And of course you're very likely to save on repair bills, since most maintenance is DIY. Classic sewing machines can be maintained and even repaired by the user with some basic mechanical skills.
The Fun Factor: There is something very tactile and satisfying about using a mechanical machine. We lack that tactile interaction with our devices today - we scroll and touch screens but we no longer use buttons or levers or knobs. On a classic sewing machine, you fine tune your stitch length, stitch width, tension, presser foot pressure, etc. You ease that knob or lever to just exactly where you want it. Yes, you have to raise the presser foot and cut the thread by hand. Yes, you have to turn the hand wheel to put the needle in the up/down position at the end of your seam. But for people who sew on VSMs, that is a nice change of pace in a high-tech world - for many of us it is WHY we sew.
Backup System: A VSM can be the perfect complement to your high tech machine. If your Binford 2000 Ultra-Zillion Stitch Embroidery/Quilting/Cappuccino Making machine ends up in the shop, you have a reliable backup. Or if you are doing long, straight seams which run up the stitch count on your $2000 machine then you can do those on your mechanical straight stitcher without depreciating your main machine. Some people even get a cheap VSM and set it up with a buttonhole attachment for a dedicated buttonhole machine (you have to try it to really get how great these buttonholes are.)
The bottom line is that these machines are so cheap, that you have little to lose to try one out. Worse comes to worst, you're out $100 +/- if you don't like sewing on it, but at least you'll still have a backup machine in case you ever need it.
