Yesodei haTorah 1:9 (quoted by others) does not entirely say that G-d's emotions are for the ignorant, the as per the posed question. He writes "ואמתת הדבר אין דעתו של אדם מבין ולא יכולה להשיגו ולחקרו -- the truth of the matter cannot be understood by the human mind, and it is unable to grasp it or study it." Descriptions of human emotions are due to the limitations of humanity and human communication. I don't see anything there about it being more for the ignorant than anyone else.
In fact, all people, even the ignorant, are expected to know that these are metaphoric. This is why Maimonides includes their rejection in his 13 Articles of Belief in his commentary to the Mishnah (intro. to Sanhedrin's ch. Cheileq). The list is his notion of the minimum one must believe to be a Jew in good standing, and that includes Divine incorporeality and a lack of actual emotions. (See also Guide to the Perplexed 1:40).
In Dei'os 1:5, the Rambam gives a second reason why G-d describes Himself using the terminology of emotions, desires and character traits. After describing the way of the wise, to follow a middle measure (middah) with respect to each character trait (1:5), he writes:
We are commanded to go in these middle ways, which are the good and upright ways, as is says "and you shall go in His Ways" (Devarim 28:9).
So was taught as an explanation of this mitzvah, that just as He is called Gracious (Chanun), you too should be gracious; just as He is called Empathetic (Rachum), so too you should be empathetic; just as He is called Holy (Qadosh), so too you should be holy. Along these lines the nevi'im called G-d by these references, "slow to anger and of great lovingkindness -- Erekh Apayim veRav Chessed", "Righteous -- Tzadiq", "Upstanding -- Yashar", "Whole -- Tamim", "Mighty -- Gibor" and the like. To let you know that these are the good and straight ways, and a person must conduct himself according to them, and resemble them according to his ability.
Two side-notes about this quote: First, the original medrash doesn't have the word "niqra -- is called", saying "Just as He is Gracious... He is Empathetic..." Our sages were comfortable continuing the biblical idiom. It was the Rambam who felt a need to spell out that we are only using the language, and do not actually mean to say Hashem has these attributes.
Second, the term for "slow to anger" is "erekh apayim", "of long nostrils", or "slow to flare His nostrils in anger". The flaring of the nostrils is a frequent idiom for anger in Biblical Hebrew. Still, in our context it means that taking the verses literally would mean not only attributing to G-d a temper, but also a nose.
Here the reason for describing G-d using emotional terminology is that He describes Himself in ways we can emulate. Divine Patience (e.g.) is not only something we see in G-d because we are limited to describing things in accord with our own experiences. It is also an image Hashem portrays of Himself to teach us to be patient.
And that motive certainly doesn't only apply to the ignorant.