Professional development for in-service teachers has long assumed synchronous participation as the pedagogical norm, positioning asynchronous formats as pragmatic concessions to logistical constraint. This Perspective Paper develops the notion that asynchronous-first design is not a compromise but an ethical imperative, grounded in recognition of the structural realities of teachers' professional and personal lives. Drawing on scholarship on interrupted academic trajectories, time poverty, equity in online learning, and the political economy of professional learning, the article advances three interrelated claims: that synchronous participation carries hidden costs disproportionately borne by practitioners navigating care responsibilities and precarious employment; that asynchronous formats enable forms of cognitive engagement that synchronous delivery constrains; and that access to professional learning should not be conditional on temporal availability. Implications for accreditation policy, micro-credential design, and the selective use of optional synchronous moments are discussed. The article repositions asynchronous-first design as evidence of institutional commitment to equity rather than accommodation of constraint.