What I like most about Mowinckel is - what at least appears to be - his sensitivity and openness to the reality and impact of the divine within Israel's history. In a German language biographical sketch of his life I read that at some point he went through something of a "religious awakening." Perhaps it is this is that comes to expression at various points in his work on the cult (apart from his dependence on the anthropologist Grønbech) ...
For example, he summarizes his entire work on the psalms as follows:
The present author has ... endeavoured to apply a really cult-functional intepretation, and ... to prove that the psalms of the Psalter, on the whole, are real cult psalms and an expression of that experience of God which the cult seeks to further (p. 34; emphasis, here and elsewhere, mine).
Like rhythm and tune it is a way of expressing the sense of rapture and sublime abandonment. It is a reaction to the encounter with the holy. ... Together with cultic song goes the dance, which is a common way of expressing the encounter with the holy. ... At a higher level it develops into an expression of joy at the encounter with the Holy One" (p.9; note the move from "holy" in general to "the Holy One" in particular).
the visible and audible expression of the relation between the congregation and the deity" (p. 16).
It may often look as thought he initiative lies with the congregation, on the human side. But seen from the point of view of cult and religion it is rather the other way round: the initiative lies with God. True enough, it is man that 'searches for God,' 'seeks God,' but he can, and odes so, because the deity first 'revealed himself' and taught man where and when and how to seek him. This is a fundamental idea of all religion, and not least in Israel. The deity represents a reality and a power which is different from the human, a belongs to the sphere termed 'the holy', he is experienced as something 'different' and 'separate' - ... Through the cult this effective [!] and wonderful 'power' is imparted to the partakers, the congregation or the society.