Is Hercules Capital a good investment?

I’m wondering if $HTGC (+0,72%) is actually a good long-term pick for a dividend portfolio. I checked it out and its price has stayed pretty flat over time—low volatility, but not much in terms of growth either. On the flip side, its dividend has been going up for 8 years straight, and the yield is 10% or even higher. That makes me curious about how sustainable it is and if it could really work as a solid income source down the road, especially if things stay steady or get better. It seems appealing, but I’m not sure if the returns justify the risk, or if it's better to diversify elsewhere.