Kugler's account of Angelico in 1842 makes in passing the point about purpose, but in the end Kugler provides a clear example of the kind of attitude which is challenged by Ruskin's diary entry of 8 September 1849, which associated Angelico with Veronese and Titian, and at Works, 9.449, where he is 'consummate' as draughtsman and colourist. (Kugler's account is also challenged in a summary of Angelico by Pope-Hennessy, in 1974.)
Kugler uses the word child-like of Angelico, but the meaning does seem to veer towards childish, and an acceptance of views which Ruskin seeks to challenge:
This profound serenity of feeling, this pure and holy frame of mind, this confiding devotedness, form the never-failing characteristics of Fra Giovanni's works. He knew nothing of human anxieties, of struggle with passion, of victory over it; it is a glorified and more blessed world which he endeavours too reveal too our view. He seeks to invest the forms he places before us with the utmost grace his hand could lend them; the sweetest expression beams in all their countenances, an harmonious grace guides all their movements, particularly where the action is expressed by the treatment of drapery. The most cheerful colours, like spring flowers are selected for the draperies, and a profusion of golden ornaments is lavished over the whole: every auxiliary has been employed that could give a new glory to these holy subjects. With a peculiar religious awe he adheres scrupulously to traditional types, and ventures on none of the innovations which were already introduced into art at Florence; these would have been a disturbing element too the childlike serenity of his mind. Of all artists, Fiesole, as we have already observed, is the most perfect example of this style, but in him likewise it appears most decidedly in all its restrictedness. He is inimitable in his representations of angels and glorified saints - weak, timid and embarrassed, when he introduces man in his human nature. Not merely the rancour and hatred of the foes of Christ, but all determined action is feebly expressed: his figures, even when in momentary repose, are deficient in apparent power to act, though the act to be performed may be the highest and the holiest; thus his representations of Christ, in whose form human power and divine sanctity should be equally prominent, are everywhere unsatisfactory, frequently unworthy. ( Kugler, ed. Eastlake, Handbook of the History of Painting, Part One, The Italian Schools, First Edition, p. 90)