The digital nomads are going to soak up a good 3 to 5% of the total housing on a permanent basis, that's a pretty good dent in the reservoir. Tourists predominantly stay in hotels or other short-stay places. Though AirBNB and so on also result in the conversion of some of that available housing into short stay 'hotels' which will put more pressure on that reservoir. Typically in any city the vast bulk of the housing is spoken for, and only a relatively small part is available for newcomers or people that move out of their parents place when they come of age.

So I would not underestimate the impact even if it is only 10 to 20K individuals.