Accel 3 click, carrying ST's H3LIS331DL, is a high-g accelerometer. While it’s cousin, accel 2 click (with a chip from the same vendor) has dynamically selectable full scales of ±2g/±4g/±6g/±8g/±16g, accel 3 click has ranges of ±100g/±200g/±400g.
Low-g accelerometers excel at detecting fine motion (for device orientation, or analyzing your ping pong bat swings); high-g accelerometers are more at home when tasked with shock detection, impact recognition and concussion detection.
Here’s an exaggerated example: if you used high-g accelerometers to detect screen orientation, you would need to slam your phone against a table or a wall every time you want to switch from portrait to landscape. On the other hand, if you used low-g accelerometers for collision detection, airbags would blow up in your face every time you went over a speed bump. So use each one in an appropriate scenario.
Otherwise, since both chips are from ST, Accel 3 has similar features to Accel 2: both I2C and SPI interfaces are available, selectable by a row of four jumpers. If you use I2C, another jumper will let you choose the I2C address. Additionally – and this is different from accel 2 – here you also have a jumper for choosing which of the chip’s two interrupt lines will be connected to the mikroBUS™ INT pin.