Star trackers are very similar to equatorial mounts. The most obvious difference is that they are smaller and more portable. There are a couple of key differences between the two worth noting. To start, star trackers only track in one axis (right ascension), whereas equatorial mounts (EQ mounts) track in both axes (right ascension and declination), which makes EQ mounts significantly more accurate when tracking. For wide angle lenses, such accuracy is often unnecessary. As a result, star trackers are more than adequate for a DSLR or Mirrorless camera and a medium focal length lens. Additionally, most star trackers use a counterweight that's much lighter than the actual payload, if they include one at all.
Theoretically, the lack of a sufficient counterweight can lead to balance issues, but this is rarely an issue unless you're using a heavy lens or telescope. In that case, you might be best served by an equatorial mount. To sum it up, star trackers are perfect for a lightweight travel tracking rig. They are best paired with a DSLR or Mirrorless camera and lens for wide field astrophotography. Equatorial mounts are much heavier and less portable, but can carry a much heavier payload such as a telescope and other imaging accessories.