Couldn't we technically bypass gateways, trade on only decentralized exchanges (which we can clone for multiple altcoins) and transact in bitUSD directly? BitSapphire is making an app to enable this...
The way I look at it is that we could wait for services to be built around BTSX and bitassets, but while we are waiting it could be beneficial to solicit companies already working in the space that might could implement it faster. I think the more options the better when it comes to payment processors and exchanges anyways.
I think getting added to already existing payment processors increases that likelihood a website or service will accept BTSX or bitUSD. You can't just expect them to all drop their current payment processors for one that is newly created that accepts BTSX or bitUSD. Coinpayments.net and Gocoin for instance, already have an extensive network of websites using their shopping cart plugins.
The decentralized solutions aren't ideal IMO in that you can't pay a website requesting Bitcoins for their products or services with BTSX or Bitassets.. There is no way to exchange them in a truly decentralized manner. Getting payment gateways on board will be the 3rd step to this campaign. To make it more likely gateways and payment processors will adopt BTSX and Bitassets, I think it is important to get added to a couple more reputable exchanges.