Sometimes a story cannot just be linear. Certain times it can, yes; there are always exceptions. But you run the risk of being boring if it is used a lot.
A different perspective can show the reader a different point of view and a new understanding of what the main character of the scene is portrayed as, or things you wouldn't see from the POV of that character.
Two parents may be talking about something that makes sense to adults, but a child who has snuck down to the dining room to listen is going to hear and see the situation totally different.
Now you can use this writing tactic for your stories benefit, but you have to also be careful not to let that new perspective character seem like the main characters in what they experience and express about it.
They should not feel think or have ideas like you would read from the main character's POV, otherwise you destroy the spell of the reader. The child also thinks a different way with its own opinions and the narrator of the child should have a different way of narrating the scene. It could be the narrator uses the child's terminology, or open the reader up to the child's philosophy.
Of course there are different POVs that you can use, and this is how writing is like art where you have many tools to make a picture. It all depends on how you use them.
Please leave comments in the comment section on how you feel about point of view and perspective. Until next time.