> Bitcoin isn't inherently deflationary.
While the supply will keep growing for quite a while, eventually it will stop growing. And lost coins will ensure that the supply keeps dropping beyond that point. Bitcoin can only avoid being deflationary in the long run if demands drops faster than supply.
> An inflating currency would never catch on.
Like US dollars? Or Euro?
Both of which are not just used where they are legal tender, but are also widely used for international trade, by choice.
> It's a hot potato situation of "I don't actually want to own it because it's decreasing in value. If I do have some, I want to dump it on the next sucker as fast as possible to minimize my losses."
This is an issue if the inflation is rapid. If the inflation is slow and steady, it's a benefit: It means the value of currency that is inactive - because someone put cash in their mattress for example - steadily diminishes, which gives you a reason to ensure your currency holdings are put to use, whether by spending them, investing them, or lending them to someone who will invest them (e.g. in the form of bank deposits). It helps stimulate economic activity.
As long as the rate of inflation is low enough, people are relatively insulated from the negative effects - you won't really notice price changes from day to day or month to month much -, and the yearly inflation can be accommodated when your salary is adjusted.