Any signature campaigns that actually pay in prominent altcoins like Litecoin, Eth, Dash or similar top alts that are high on market cap?
The coins payed for signature campaign is only bitcoin, some pay with both bitcoin and their coins. But when it comes to another campaign (bounties campaign) you will only be paid in their coin or in stakes.
Yes, it has the different section of both the altcoin payments and Bitcoin payment. The signature campaign you find in the Bitcoin section will be paid through Bitcoin and in the Altcoin section, they will pay the concerned altcoins. Some of those coins will have value in the market and some don't have any value in the market.