Speed · Plain-English answer
Usually a VPN adds a few milliseconds of latency, because your traffic travels via an extra server. It can occasionally lower ping when your provider routes traffic badly to a game server, and it helps against targeted DDoS attacks in competitive lobbies. For most players it is neutral rather than an upgrade.
Every packet to the game server detours through the VPN server, so the round trip gets longer by however far out of the way that detour is. Connect to a VPN server sitting between you and the game region and the penalty can be tiny. Connect across a continent and it will not be.
The often repeated claim that VPNs reduce ping is true only in a narrow case: when your ISP's route to a particular game server is poor, the VPN's route may be better. It happens, but it is not something to expect.
The strongest case is DDoS protection. In peer to peer lobbies and competitive communities, opponents who obtain your real IP address can flood your connection. Behind a VPN they only ever see the server's address, which can absorb far more abuse than a home line.
A VPN also helps when a network blocks game traffic, such as university halls, and lets you join region locked servers by appearing elsewhere. ROOT runs WireGuard, which keeps the added latency as small as the geography allows, and you can check the effect yourself at /tools/speed-test/.
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