GTP is comparatively equivalent to ATP as it is also utilized as an energy source and phosphate donor in metabolic processes.
GTP can be used to easily convert to both forms and have a similar Km (Michaelis-Menten constant which defines the concentration of substrate when the reaction is at half of the maximum velocity) as that of ATP.
Hence, it can easily be converted to ATP by the enzyme nucleoside diphosphate kinase.
Thus, GTP is also utilized in specific processes such as signaling, protein synthesis, etc.