TBH, the only advantage I can see to the Time system is that it avoids this pedal wear problem (presumably because the cleats are a softer material, hence subject to more wear). And it gives you oddles of float, if you like that sort of thing (I'm not keen, but it doesn't seem to be doing any harm).
SPD is much easier to engage quickly, and doesn't require the foot to be re-positioned between unclipping and re-clipping, which gives it a substantial advantage for actual MTB riding, but doesn't really matter on a 'bent. It's also about half the price.
FWIW, road cleats are fine on a recumbent, until you're in an unstable one-foot-down scenario, in which case they're a liability. I have a set because reasons, and I'm using them for racing because the shoes they're attached to are pretty good for racing, but I've decided that mountain bike cleats are the way to go for the real world.