Does Swiffer actually work or am I just wasting money?

Swiffer works fine for quick cleanups and light dust, but it's not a substitute for actual mopping if you want your floors genuinely clean. Most people find it useful for maintenance between deeper cleaning sessions - it picks up surface dust and crumbs pretty well. The main waste is usually the refill pads, which are pricey for what you get, so if you're doing it mainly to avoid breaking out the mop every few days, it's reasonable. If you're using it as your only floor cleaning method, you're probably not getting floors as clean as you should.