I thought I’d paste my response to her query on the rationale of using incense in worship here.
(A) Whatever is pleasing and costly to humans is plausibly offered to God as a sacrificial gesture (in the double sense of the gesture of renunciation by the human and the gesture of endeavouring to please the deity);
(B) It visibly ascends to heaven, where (presumably) God can relish its aroma;
(C) It signifies prayer (Ps 141:2, ‘Let my prayer be set forth in thy sight as the incense; the lifting up of my hands as the evening sacrifice’), especially important since after the destruction of the Temple and the incense-alter therein, it was deemed that observance of daily prayer fulfilled the commands in the Torah to make daily sacrifices, morning and evening.
(D) Its pleasing aroma adorns the liturgy, in keeping with the premise that we ‘worship the Lord in the beauty of holiness’; it is fitting that worship communicate via all the senses that something splendid and glorious is taking place.