zenMichael has a good point here. I think this statement is loaded and it applies to all gods and their relationship with worshippers and that is probably why Bugg got startled.
Bugg has elemental power. In that aspect he probably does not need any worshippers and does not seem to desire any either
RG
"Throne" here is probably a placeholder for an "altar" and the act of worshipping
Tehol's point is why do gods who dont want to be worshipped end up getting workshipped anyway. Fundamentally, it is because people are selfish and worship for selfish reasons or they are stupid.
Gods get some power out of it and so do the worshippers but some Gods dont like this arrangement.
The Errant seems to have broken out of this dependence. He is in no way compelled to respond to any of his worshippers.
The Letherii still worship the Empty Throne though and are able to fully use the the magic of the empty hold but the Errant clearly states at later points that that he does not do anybody any favor
But the Letherii worship the empty throne anyway. This implies two things.
They like this arrangement of not having a god (and thereby not being restricted to the god's moral code)
and SE likes to imply that the Letherii pursuits are vaccuous.
So the statement is powerful in terms of summarizing the greed and stupidity of the Letherii but not in terms of revealing any big secret (such as Who is QB, who is Ruthan)
The nature of Godhood in MBotF is very interesting and probably needs its own dedicated thread.