You shouldn't be happy. This is how all smoke detectors start going bad. First, they try smoke. Then steam. Next thing you know, they're doing household dust, air-borne particulate matter, then petroleum-based fumes. It's downhill from there. It'll join a gang..... start drinking heavily..... get a tattoo.
Next thing you know, your precious smoke detector is calling you from jail, having been arrested for breaking into a pharmacy in order to steal 9-volt batteries.
If you don't stop your little one now, the end of the road willl be a federal charge of trespassing on government property when it tries to steal americium-241 in order to rejuvinate it's sensor. Federal facilities are no place for a Kiddie.