High-ankle cycling shoes—basically boots that extend well above your ankle bone—are designed for specific situations where protection and weather resistance matter more than mobility. They shine in downhill and aggressive enduro riding, where pedal strikes, rock impacts, and trail debris are real hazards. They're also a great choice for winter riding or nasty conditions, since the extra coverage keeps your feet warmer and blocks out rain and mud.
The trade-off is significant, though. That taller upper restricts how freely your ankle moves, which you'll notice during pedaling and especially when hiking sections of trail. High-ankle shoes are also heavier and less breathable than low-cut options, so your feet will run hotter on long rides in warm weather.
For most road, XC, and general trail riding, low-cut or mid-ankle shoes are the better pick. Save the boot-style shoes for downhill days, harsh winters, or bikepacking through rough, wet conditions where that extra protection really earns its keep.