Why do I have to specify the CPU architecture when I create an image from a volume?

ARM and x86-based instances (Development Instances and General Purpose Instances) are using a different instruction set, this requires to specify the architecture of the platform when creating an image from a volume.
An ARM CPU is using a Reduced Instruction Set Computing (RISC) architecture while an x86 CPU is using a Complex Instruction Set Computing (CISC) architecture.
Hence, ARM architecture uses a simplified instruction set which results in power efficiency, making it ideal for mobile devices. Therefore ARM64 virtual instances are ideal to develop and test mobile applications.