Re: Are campaigs only the major source for earning BTC ?

I think that it is the only major leading source from where we can actually earn bitcoin
but i am not sure about trading

Exactly it is one of the major source of earning bitcoin and although mining and trading are more bigger source but they need monetary investment first to earn bitcoin.While mining is not everyone's cup of a tea,trading involves risk of losing.
Signature campaign on the other hand does not require any monetary investment but one has to invest time in it yet it is completely risk free.

I agree with you for signature campaign one has to give full time to earn free bitcoins but apart from this in altcoin section we can earn free coins through doing small tasks like social bounty, translation.

Earning bitcoins from different sources will depend on the skills that you hold, if you have multi skills then you can earn bitcoins from multiple sources and will not have to depend only on signature campaign to earn them, more skills will add more value to your earnings and its always good to have multiple sources of income.