Drawbacks of the glass-capsule fuse include the fuse length - is often related to its amperage rating.  This means you may not be able to use a different amperage rating when you add or remove a load from an existing circuit.  A special tool is needed to remove glass fuses from the fuse panel without breaking them. Possible for the metal strip to blow inside the metal cap, where its condition is not readily visible.  Fuse ratings are embossed in the metal end cap or etched on the glass capsule.  In either case, it's often difficult to read the marking without removing the fuse.