Bitcoin is based on an increased demand an a deflationary supply, however that eventually leads to a coin that people don´t use to trade or to transact. What do you think that the emission rate of a crypto should be to be used as a coin? Any automatic mechanism to adapt exists?
Bitcoin grows in price not because it is deflationary. As a matter of fact, it has been quite inflationary so far. New coins are created every hour (actually, every 10 minutes on average), so it is inflationary. It grows because demand exceeds supply and that can be true in respect to both inflationary and deflationary coins. If you really want to ask whether a small inflation is better than deflation for a currency, then I will likely agree with you.
You are right , bitcoin has certain inflation for the moment in terms of emission. But it is deflationary in term of what you said: the market. It would be the same for any fiat.