It is often said that teaching on the sacraments is not clearly spelled out in the Bible. Therefore since it is unclear, we should not get too worked up about differences. However, I wonder if there is more to this question than meets the eye. Pierre-Charles Marcel, in his The Biblical Doctrine of Infant Baptism, writes:
The celebrated dogmatician H. Bavinck has well remarked that the doctrine of the sacraments has always been the shibboleth, the touchstone, of every dogmatic system. It is there that the principles from which one sets off in the Church and theology, in questions of faith and life, find there practical and concrete issue. The doctrines of the affinities of God and the world, of creation and regeneration, of Christ’s divine and human natures, of the modes of action of the Holy Spirit, of sin and of grace, of spirit and of matter, are all more or less present and implicit in the doctrine of the sacraments. The diverse roads of theology converge, whether one wishes it or not, sooner or later, consciously or unconsciously, in the highway of the sacraments. It is necessary to take this into account. (p.17)
I have felt for some time now that in any debate on baptism, for example, there is limited value in discussing the mode and the recipients by reference to NT texts without first going over some other, perhaps more basic ground. For example, if someone says to me, “Just read the New Testament!” when discussing the recipients of baptism, that says to me that there may be a difference between us in our doctrine of Scripture. It will also hint at the perceived relationship between the epochs of biblical history and the God-given covenants. And so it could go on.
So, rather than the sacraments being unimportant details, they point to more deeper questions which cannot be considered unimportant.