Parshat Behaalotcha #1: Chovav as witness, or guide?

One of the more interesting parts of the parsha is the short exchange between Moshe and Chovav, his "Chatan" (father-in-law, = Yisro, but see my next post)

Bemidbar 10:29-32:

וַיֹּאמֶר מֹשֶׁה, לְחֹבָב בֶּן-רְעוּאֵל הַמִּדְיָנִי חֹתֵן מֹשֶׁה, נֹסְעִים אֲנַחְנוּ אֶל-הַמָּקוֹם אֲשֶׁר אָמַר ה, אֹתוֹ אֶתֵּן לָכֶם; לְכָה אִתָּנוּ וְהֵטַבְנוּ לָךְ, כִּי-ה דִּבֶּר-טוֹב עַל-יִשְׂרָאֵל.
וַיֹּאמֶר אֵלָיו, לֹא אֵלֵךְ: כִּי אִם-אֶל-אַרְצִי וְאֶל-מוֹלַדְתִּי, אֵלֵךְ.
וַיֹּאמֶר, אַל-נָא תַּעֲזֹב אֹתָנוּ: כִּי עַל-כֵּן יָדַעְתָּ, חֲנֹתֵנוּ בַּמִּדְבָּר, וְהָיִיתָ לָּנוּ, לְעֵינָיִם.
וְהָיָה, כִּי-תֵלֵךְ עִמָּנוּ: וְהָיָה הַטּוֹב הַהוּא, אֲשֶׁר יֵיטִיב ה עִמָּנוּ--וְהֵטַבְנוּ לָךְ.
And Moses said unto Hobab, the son of Reuel the Midianite, Moses' father-in-law: 'We are journeying unto the place of which the LORD said: I will give it you; come thou with us, and we will do thee good; for the LORD hath spoken good concerning Israel.'
And he said unto him: 'I will not go; but I will depart to mine own land, and to my kindred.'
And he said: 'Leave us not, I pray thee; forasmuch as thou knowest how we are to encamp in the wilderness, and thou shalt be to us instead of eyes.
And it shall be, if thou go with us, yea, it shall be, that what good soever the LORD shall do unto us, the same will we do unto thee.'

Thus, we have a non-Israelite, who wants to go home, and Moshe is trying to convince him to latch on to the Hebrew nation, and join in their destiny.

Why does Moshe want him to stay? Moshe says כִּי עַל-כֵּן יָדַעְתָּ, חֲנֹתֵנוּ בַּמִּדְבָּר, וְהָיִיתָ לָּנוּ, לְעֵינָיִם, which is taken by Chazal to mean this Chovav will go with them through their travels through the Midbar, and witness the miracles Hashem will do for them. Thus, לְעֵינָיִם means as eyes to witness the great things Hashem does for them. There is more to this midrash than just this interpretation of וְהָיִיתָ לָּנוּ לְעֵינָיִם; there is also the next pasuk, ְהָיָה, כִּי-תֵלֵךְ עִמָּנוּ: וְהָיָה הַטּוֹב הַהוּא, אֲשֶׁר יֵיטִיב ה עִמָּנוּ, that when we experience the good that Hashem does for us as we travel.

An alternate explanation also seems possible to me: that כִּי עַל-כֵּן יָדַעְתָּ, חֲנֹתֵנוּ בַּמִּדְבָּר is the reason Moshe wants him to travel with them. Moshe, and the Jews who were stuck in Egypt, were not familiar with the area of the Midbar. Chovav perhaps knew the area better. Thus, כִּי עַל-כֵּן יָדַעְתָּ, חֲנֹתֵנוּ בַּמִּדְבָּר, "because you know our encamping (or travels) in the Midbar (wilderness)." Chava knew the area and could tell them where they are, what the surrounding areas and nations were, where one might find an oasis, etc. Sure, Hashem told them when and where to travel, but a guide who would tell them where they were and who knew the territory would be comforting. Thus, וְהָיִיתָ לָּנוּ, לְעֵינָיִם, you will be for us as eyes, so that we can know where we are going in this unfamiliar territory.

It is not immediately clear whether Moshe convinced Chovav to stay.

Also, I thought about the parallel/contrast to Ruth's joining the Jewish nation, in which Naami tries convincing Ruth to go back to her home and family, and does not promise that life will be good, and Ruth in spite of this goes along.