The GNU Assembler as uses different characters depending on the architecture to specify single-line comments, such as # on x86, ; on 29k, or @ on ARM. Moreover, regardless of platform, C-style comments are also supported (/* */).
Is there a technical reason for different comment styles on different architecture? The multi-line comment suggest no, as it works on any platform - however if there is no technical limitation on the characters that can be used for comments, why design the assembler to require different comment styles on different platforms (for single-line comments)?