The film does NOT feel like a sci-fi nor CGI film nor "manga/comic" at all (less the CGI portion or exaggerated facial expressions). In fact, if I were not told that a lot of scenes and backdrops were CGI created, i would have thought that they were reconstructed physically specifically for the film.

Answering your question more directly (i.e., would it interest a western audience)? 

My answer is a YES ... but probably the adults more than the young ... also, it is more mainstream/commercially viable rather than cryptic or film fest kind of "art" film ... 

In essence, it would interest those who like a family oriented drama, or those who are nolstagic about the good old days, or those who like uplifting films ... its themes typically cut across all culture and generation ... in particular, it is about HOPE ...

But some words of caution:

(i) if you expect it to be another Titanic (sweeping away many awards), you may find some difficulty reconciling ... you may feel that it is a GREAT film, but you may not have it sweeping all awards ... I like the cinematography, its rather interesting soundtrack and some of its later scenes ...

(ii) you must buy their acting (which are "too expressive" at times, but common in Japanese films) ... you must also buy its story ... it works slowly, and by the end, I think you will like it ... although it does not feel like Titanic, I think it is worth watching ...