I’m no marketing expert.

Doesn’t sound all that wrong to me.

Since they are profitable, they are not that dependent of the initial investment anymore. They did not expect to get this many users, and then send the shirts as thank you.

They money could have been used to hire new employees, but they decided to say thank you. I cannot criticize this since it does not seem to doom the company, while it might slow down a bit.

One of the emails explicitly mentions them being profitable since recently.