Should my 7 year old son wear glasses if his myopia is very minor?

Only for far things: If most of his world is near, he need not wear the glasses. I tell parents not to fuss with a child who does not want to wear their glasses--you have enough other things to fuss with them about. He will need stronger glasses as he ages and by then he may want the luxury of good vision far away, but if it isn't needed it will not make that happen.

Hard to say: Vision is similar to 2 side by side cameras focused on the same objects. If one eye is stronger than the other, the brain will prefer the sharper image & may choose to fade out/turn off the weaker image creating a long term vision loss called amblyopia. If both eyes have exactly the same vision this would not be an issue. You should ask the eye doc about specific needs in your case.