In good/ok weather, definitely. Lots of little shops and cafes, boats to look at/go on (trips to St Mawes or just across the harbour to Flushing). Beaches. There is a small, but family friendly and free art gallery. There is a brilliant playground in Kimberley Park just up the hill out of town. Walk to Pendennis point for great views over the bay and ice creams. The museum is the go-to option for most local families in wet weather, but on a nice day it wouldn't be first on my list for a day in Falmouth.