They might or might not be a net positive. I think it's more complicate. It's not just money, but also where the money is going and what it is achieving.

E.g. a lot of wealthy foreigners will increase the rent, prices for restaurants and services. Oftentimes, the quality of restaurants/services might go down (because if you cater to a crowd that only stays a couple of months, there's not the same need to get these people to come back. That are changes that are often received negatively by the locals.

Foreigners also make use of public services like streets, public transport etc., often without paying income tax.