Issue with Teams RSC Permission TeamMember.Read.Group

Thanks for the explanation.
So the RSC permissions are only for standard channel.
Then I can see a usecase for ChannelMember.Read.Group
But ChannelMember.ReadWrite.Group makes no sense in that context.
Members of Standard channels cannot be written. All team members are automatically members of all standard channels. The "write" scope makes no sense.
Can you given one example what I could do with this api? I guess I can do the same thing as with only the read scope. I can read the channel membes, but what can write with this API?