I use my se215s for workouts (mostly indoor cycling in a trainer and light weights) and haven't had any issues in two years of use. Only noticeable corrosion is the "Shure" logo disappeared on the right outer pod. I typically sweat moderately, and usually take care to wipe phones and cords thoroughly after each workout. I avoid swabbing with alcohol, but have used slightly soapy water or witch hazel in solution if my sweat has been excessive or especially salty. I try not to clean with liquid near the sensitive contact points where the cord meets the pod.
I also sleep wearing them sometimes, to no ill effect. I use the large "olive" tips, and find them durable enough for months of use.
Something I find helpful to avoid cable-snags during workouts: Try wearing the cable behind your head (cinch it up mid-neck) and let the cable run down your back. Depending on your back length, shorten the cable by looping excess with a fastener (I've used everything from those wire ties that come with electronics to a clothes pin). You can tuck a portion of the excess cable into a pocket or the elastic of your sweats/shorts.
As far as sound is concerned, the se215 isn't audiophile, but it's excellent for its price. Isolation is very good, almost dangerous in the wrong environment (I can't use them for road cycling because I lose all outside audio cues). I agree with the comment about "boring" sound, to a degree. The sound, to my ears, can be a touch muffled in "busy" music passages with much bass and mid action. But they can be surprisingly detailed in less congested sections. (They are a single-driver IEM, after all, so there must be compromises.) Overall, I think these are a bargain headphone in the best way. Some of the "boringness" is actually akin to flatter headphone signatures, which I find less fatiguing over long listens. Once you adjust to it, there is much to enjoy
Based on my experience, I'd recommend the se215 for workouts, provided that you are aware of the risks. It's a fairly tough IEM, but you're putting stress on it that could cause damage. To me it's worth risking a $100 set of phones to have very decent sound available to relieve workout boredom. If I damage or misplace them, it's not a tragedy, like it would be with a higher-end IEM.