Indeed, the boundary between tourists and residents is porous. Capital cities attract a transient population from week end visitors to interns or workers who stay a few weeks, to summer visitors who stay a season, to students who stay for a few years, to proper residents who stay a decade or more. All of them are a source of ideas as well as a source of income for Berlin's industry. "Das ist auch gut so." Hence Berlin needs to cater for all. That includes providing substantial, centrally located living space (whether hotels or apartments) for short-term visitors.