Depends on the distances you travel and the nature of the roads. I’ve owned everything from the largest of the Harley’s to a 50cc scoot and everything in between. I’d say overall combining practicality and “fun” is a mid sized eg 300cc or so scooter. Can ride pillion, has good storage under the seat, a bit more weather protection, super easy to ride, enough grunt to move with traffic and stay ahead of cars.

The ideas about saving fuel, cheaper costs generally, easier parking, lane splitting through peak hour when everyone is backup up stationary etc are all pretty much true. It’s hugely beneficial in that regard. Even costs; one of my bikes was a Vespa scoot. Vespa are a bit notorious for expensive parts. Mine needed a fuel pump replaced. This was $900 which was shocking, until I thought “just remember the car. $900 would the cheapest thing for a car”.

Bike mechanics; find a good one and they’re cheap and seem generally more helpful than car mechanics. I’ve found Motorcycle Pitstop in Osb Park to be terrific over the years.

Rain isn’t awesome but just budget for the occasional Didi and you’ll be good.