You may be confusing plausibility with mental effort - it's certainly easier, in terms of mental effort, to believe in creation, but it means ignoring multiple independent lines of evidence, gathered over 200 years, supporting common descent, ignoring the elegant and demonstrable natural mechanisms by which it occurs, and ignoring the implications of the practical applications of those discoveries and mechanisms.
As an explanation, creationism lacks explanatory power, being untestable, giving no understanding of the diversity of creatures, their similarities, differences, and histories, and it gives no framework of understanding to unify our knowledge of them in the widest contexts. It also means uncritically accepting the existence of a contradictory, ill-defined, invisible entity with supernatural powers, for which there is no evidence or explanation, that raises a host of unanswerable questions, that contradicts all we have learned of how the world works, and that anthropological evidence points to being one of many human origin fictions confabulated to cover our ignorance, and later co-opted as a means to societal order and control.
In short, for those without access to scientific knowledge, it's a belief born out of ignorance, and for those with access to scientific knowledge, it's a belief of willful ignorance.