Terminals only allow overwriting the visible content.

https://symfony.com/doc/current/console.html#output-sections should make that clear.
the first use case mentioned in the page (showing multiple progress bars) is fine as progress bars don't grow in height. However, the second mentioned use case (appending content in a table) is more risky (if the table is in the first section and you only append to it and the section is a small one in height, it will work. But that won't work if you try to have 2 sections showing tables in which you append).

See symfony/symfony#35012 for some discussions about it.