Basically what tailscale offers with headscale but with more sophisticated control over exit traffic, like:

1) the ability to define an arbitrary wireguard configuration as an exit node (tailscale can do this in theory, but it only works with mullvad and it doesnt work with headscale).

2) the ability to write sophisticated exit traffic rules (e.g. intranet.myemployer.com requests get routed via one home server running my company's proprietary VPN, mybank.com gets routed via another home exit node, default traffic through mullvad, etc.)