A lot of people are sitting behind a NAT of their ISP.
Disclosing this ip doesn't harm you security-wise since it is not publicly routeable anyway.

Even if you have a routable IP, it is not that necessary to keep your IP private. Any website (including all advertisments, javascripts they are running, etc..) can access/see your IP.
It is necessary to communicate with you.

Any service / software / etc. which you access via the internet does see your IP address (skype, bitcointalk.org, blockchain.com, DNS-server, electrum server, ledger's server, a VPN service provider, etc.. ).

If you don't have any open ports, you don't need to worry much. Set up a firewall properly, and you are fine.