From what I can tell the new context editing and memory APIs are essentially formalization of common patterns:

Context editing: Replace tool call results in message history (i.e replace a file output with an indicator that it’s no longer available).

Memory: Give LLM access to read and write .md files like a virtual file system

I feel like these formalizations of tools are on the path towards managing message history on the server, which means better vendor lock in, but not necessarily a big boon to the user of the API (well, bandwidth and latency will improve). I see the ChatGPT Responses API going a similar path, and together these changes will make it harder to swap transparently between providers, something I enjoy having the ability to do.