The idea isn’t to have it be overpowered. Temp invincibility can really fuck with the raiding aspect of the game, but it’s something to be considered. It’s not exactly fair that your orientation when you spawn can be used against you by someone with equivalent weapons, or that you can take a hit due to a couple of mS lag before your shit renders fully and you can actually do something about it. The more players you have on a server, the more problems like this you will encounter.
Games that punish a player for being new usually don’t last very long. It’s one thing to suck, but another to encounter rampant bullshit from the first moment you ever log in.