Samarium cobalt magnets are easily peeled off. Goggles must be worn when handling them.
Leaning the magnets together can cause the magnets to shatter, which can be potentially dangerous.
Samarium cobalt is produced by a process called sintering, and all materials are sintered, and the inside is very likely to crack. The magnet does not have mechanical integrity and only has the function of preparing a magnetic field. Therefore, special mechanical systems must be designed to give the overall system sufficient mechanical reliability.