Student or Learner
Is the expression "be seen as" reserved only for situations when it is a synonym of "to be considered..." (like "white dove is seen as the symbol of peace), or can it be also used in its primary meaning - that you will see that thing in a certain shape when you find/encounter it?
For example (don't try to dispute the below sentence's verity, it's just an example)
<<That phrase is usually seen as 'cut down on', but you will also find a large amount of examples with the word 'back'>>
Can I use "be seen as" in this context, when it is not indicating a comparison, but referring to the shape/appearance of something?
Yes, "be seen as" can be used literally. I don't understand your example sentence at all, though. So I'll supply some.
"A star viewed from far away is seen as a single point of light."
"A Capital 'i' in a sans-serif font can be seen as an 'l'."