With kids, it depends on the day.
A genuine neighbourhood market under Brunelleschi's deliberately bare Santo Spirito façade — produce and household stalls on weekday mornings, antiques and crafts on the monthly fair days. The honest read for a visitor: there's very little here to actually buy or do as a tourist (it's a working local market, not a crafts showcase), the daily version is small, and the square it sits in is the city's late-night drinking hub — by morning it can be litter-strewn and hungover, the residents' noise war with the bars a constant backdrop. The reward is simply seeing a market that isn't performing for you; go for the texture, not to shop.