her rustic ways

In an adapted version of Heidi, by Johanna Spyri, Heidi was taken to live with her grandfather at his cabin in the Alps mountains, and one day, he took her to a village down the mountain.

At each stop, Heidi’s kindness brought smiles to everyone’s faces, even as they noticed her rustic ways. As she and her grandfather began the journey back up the mountain, Heidi looked back at the village with a full heart. She had made new friends in the valley as well as up in the Alps.

Why "even as" was used? I don't see any contrast, I mean isn't it natural for "villagers" to like "rustic ways"?

I suppose a village lower down the mountain was less in touch with old rustic ways than one that was further up, and perhaps more isolated--especially in winter. What exactly were these "rustic ways"?

Maybe the people who live in the valley consider those who live up in the mountains (more) rustic?

"A village down the mountain" is ambiguous. It would certainly be more accessible, whether it was on the foothills, at the bottom of the mountain, or indeed in a valley.

I suspect the villagers look down on the people of the mountain, at least to some extent. They may think that they're the sophisticated townsfolk, and the people of the mountain, who may come down only once or twice a year are unsophisticated and rural. Nonetheless, they are drawn to Heidi's friendliness.

Why was "even as" used? I don't see any contrast ...

I don't use this "even as" conjunction myself in this "contrast" sense - it sounds literary/dated. But no contrast is necessarily implied:

even
(adv)
7. even as ⇒ (conjunction) at the very same moment or in the very same way that (Collins, via WR)

So "Heidi's kindness brought smiles ... and, at the same time, they noticed her rustic ways".

The conjunction I associate with reflecting a contrast is "even though":
"Even though he was only a seven-stone (44.4521 kg 👁 Stick Out Tongue :p
) weakling, he kicked sand in the face of the beach bully, who then went rushing back to his mummy."

But I agree with lingobingo's remark in #4 in this thread that "even as" seems to be used in the same sense as "even though". And even as I was looking for that thread (under "even"), I noticed many previous threads about "even as".

Dorfli (the village) had a school and a church and all kinds of amenities. The people who lived up on the Alm lived in small rustic houses and kept goats. So the villagers were relatively sophisticated and Heidi and Peter and their families were far more rustic, and that's your contrast. (In fact, Heidi's grandfather actually has an upper-class background and is being a hermit for personal reasons, but that's not relevant to the situation you ask about.)