If you’re asking “Why should I use TCP with OpenVPN?” you’re not the only one. Your VPN service will offer you many options that can directly affect the security and enjoyment you get when you connect to it:
Tunnel Type: Usually OpenVPN or OpenConnect.
Protocol: Usually either TCP or UDP.
Port: Depends on your choice of protocol.
Cipher: We recommend using the AES-128-CBC cipher with OpenVPN.
Why should I use TCP with OpenVPN?
Most people consider UDP as the preferred protocol to use with OpenVPN. However, you may discover that TCP is slower but more reliable.
Another reason why you should use TCP with OpenVPN is stealthiness. Since SSL traffic uses TCP, port 443, you can often defeat censorship by configuring your OpenVPN to also use TCP and port 443.
Doing this makes your VPN traffic appear identical to SSL traffic.
Censors usually don’t completely block SSL would prevent access to practically every website users would want to visit.