What Are the Advantages of Having Low Ping

[Kanivakil]

Say a player with a ping of sub 30 vs players with a ping of 80-100 in a game of FFA.

[Ikaruga]

Say a player with a ping of sub 30 vs players with a ping of 80-100 in a game of FFA.

Quake is a very fast paced game, and a lot can happen in 50-70 ms. While the time period itself might seem very short indeed, it can still make a great difference if your opponent(s) don't have to deal with such a "delay".
While experienced and skilled players with smart gamelpay can counter high latency surprisingly well, and while the netcode in QL has some disadvantage for players with very low (sub 30) pings (on certain configurations), it's still noticeably easier and better to play with low ping most of the times.
Skilled enemies who are master of dodging are very hard to predict, and latency makes situations against them even worse.
You can react faster to situations with low ping, which also gives you more time to dodge attacks.
Some weapons (especially the projectile ones) are also much harder to use as the latency increases (plasmagun for example).

[vurun]

In brief, with low ping when you see a player in your crosshair - he is really there, and not a couple inches to the side. The same goes to rockets - when you see one 30 meters in front of you, it means it's not knocking at your forehead
On top of that, when two players see each other simultaneously, the one with lower ping have an advantage to shoot first and probably frag.