Short answer: yes, but not automatically. When a bin has a proper ashtray top—deep enough, with a snuffer or restricted opening, and a separate inner tray—it gives smokers a clear place to stub out butts instead of dropping them on the pavement. In busy areas, that can cut cigarette litter noticeably and reduce the risk of smoldering butts starting a fire in the main bin.
The catch is maintenance. If the ashtray fills up, smells bad, or gets mixed with ordinary rubbish, people stop using it properly. Rain can also turn a shallow tray into a soggy mess, and cheap designs let ash blow out. I’ve seen bins like this work best when they’re emptied often, clearly marked, and placed where smokers actually linger—near bus stops, office exits, and crossings.
So I’d call them useful, not magic. They work well when the design is thoughtful and the cleaning schedule is real. Otherwise they just become another piece of street furniture that looks good in a photo but doesn’t solve the litter problem.