100%. In fact, I've usually found in my career that serialization/deserialization is the largest latency contributor, except when the API call makes remote dat

100%. In fact, I've usually found in my career that serialization/deserialization is the largest latency contributor, except when the API call makes remote database requests or something equally expensive. For the critical path of, say, game state updates, it's best to keep as much as you can in-memory on-box, so ridiculously expensive operations like json deserialization really stand out by comparison. Even for enterprise web crud calls, it's quite important when you're part of a giant ensemble of web calls, some of which may be serially dependent, to worry about things like this.