It’s just that this is WWDC. Why is this conference about “what customers value”? Why can’t this one be the one where they go trough the serious features and talk to those folks.

It seems to me they just ignore devs nowadays and focus on pushing the product to consumers.

I would normally agree, but the "customers" for WWDC are developers who want to get business value out of producing apps for the Apple ecosystem, no? It's not an "industry" presentation, an E3 or CES-like event, where the goal is to feed PR to reporters to trickle down to consumers; the final audience for the presentation are the very people watching it, and that audience doesn't necessarily even use Apple devices as their primary devices—they just sell into the Apple software market, potentially as one market among the many they target.

Any talk at a WWDC keynote about e.g. new hardware, isn't because new Apple hardware is fundamentally exciting to these people; it's for the sake of reassuring them that Apple is keeping the market for their software thriving by giving the demand side of their market [hardware] reasons to buy into the ecosystem, or stay in the ecosystem. (It's also for the sake of talking about new software features enabled by hardware changes, e.g. the touchbar translating to an additional interaction paradigm for apps, or ML cores translating to ARKit.)

I don't really see how talking about emoji achieves the same goal of reassuring developers, given that consumers don't really make buying decisions based on the availability of emoji within one ecosystem but not another. (In fact, in my observation, the reverse is true; people usually avoid using new emoji until the people they text with can see them, meaning that a new emoji only becomes useful when both iOS and Android support it.)