Document structure

Hello, I'm starting to learn MongoDB, and I have a question I did not find anywhere:

Documents from the same collection may have different structure. Example:

{
    "id": "1",
    "name": "John"
},
{
    "id": "2",
    "name": "Mary",
    "age": 30,
    "isBlocked": false
}

Having a collection of different JSON objects in the same collection can cause many problems? For example, when dealing with / filtering data, etc.

Is it a mistake to have collections with different JSON objects?

Thanks to anyone who elucidates this issue, my thinking is still very much about traditional SQL.

Thanks.