The Buddhist Eightfold path that makes reference to beliefs, views: "right view" (samyak-dṛuṣṭi / sammā-diṭṭhi) or "right understanding". Because of this one might infer that Buddhism is committed to some sort of metaphysical doctrine. But having the right view or understanding merely means acknowledging that that our actions have consequences, esp. that our actions cause suffering. Yes, Buddha did talk about karma and rebirth, but many secular Buddhists, myself included, believe that there are perfectly reasonable non-metaphysical understandings of karma and that rebirth is simply inessential to Buddhism. All of the other parts of the Eightfold path are explicitly practical or have practical implications for one's life.
Unlike many religions or philosophical theories, Buddha taught that enlightenment is a practice, a process, a path, not a belief system. So I have always interpreted Buddha as a practical or ethical teacher, where "ethical" is understood in the broad ancient Greek sense of ethos: a general lifestyle or set of mental or practical habits that result in general character traits, which themselves result in flourishing or suffering. In this way, I see what Buddha was teaching as similar to what was being taught by other Ancient Greek philosophers in the West. Indeed, I notice many similarities between Buddha and various Hellenistic (i.e., post-Aristotle) philosophical movements such as Epicureanism, Stoicism, Skepticism and Cynicism insofar as all of these Western philosophical movements were first and foremost ideas that had practical application to one's life. Moreover, Epicureanism and Stoicism are similar to Buddhism in specific advice they offer of how to live well by avoiding pain, suffering and struggle. The ethos that Buddha taught was one of awareness, emotional regulation and non-attachment.
Furthermore because Buddhism isn't committed to a specific robust metaphysical doctrines it can be freely tailored to contemporary society and its unique challenges. For example, Mindfulness is a secular movement that was a direct response to the ever-increasing--in many cases overwhelming--bombardment of information and drive for professional success that is pervasive in society today. Both Buddhism and Mindfulness are practical tools for achieving and maintaining well-being in today's world. Last, secular Buddhists are free to draw on other elements of secular life that can aid in the Buddhist goal of reducing the amount of suffering, anguish, etc., such as the inclusion of science, the arts, movies, literature, poetry, etc. In this way, Buddhism has an advantage of other western religions, which are based on static doctrines and therefore must occasionally undergo reformations to be updated.