So i am an investor in bond markets and i am not so good at gambling or trading. I think one key difference is the approach. As an investor, i want to be aware of everything that i touch. I want to find value. I want to take a long term positions. To identify value, i will look at macro risk, industry risk, company specific risk, relative value and then assess the outside. Since i am aware of the risk, i can take a long term call.

A trader i believe thinks of payoffs. What is the loss given a risky event and the probability of a risky event. He will also assess the same for upside. And a positive outcome should be traded. Outlook is usually short term and most traders will not carry overnight risk. Medium term traders will trade on statistical levels.

I think the key difference is mindset and strategy. Just my 2 cents.