I once heard a conversation in which someone said they didn't care for the rendering of "okay" as simply "ok", although they accepted "o.k.", because to them "ok" seemed like it was meant to be read as a monosyllabic word, and, well, "obviously 'ok' isn't a word"
but my instinct as an esperanto speaker is to retort: tute ne, kiel ĉiuj scias, ok *ja* estas vorto.