"Mobile Bitcoin wallets don't all necessarily rely on "a centralized gateway." EG, I can tell my phone's SPV client to use a full node I run myself."
It's about mobile access
without a centralized gateway or additional software which is the only method mainstream users will realistically adopt because that is what users in 2016 are already used to. Or they can use PayPal or BitPay, both centralized services.
Sure there are ways to use Bitcoin decentralized on the move, it's just they're not exactly usable, e.g.
https://i.imgur.com/8bchO0S.jpg 
Do you think DASH's Dapi could attract more developer than Etherium? Or is it easier to write DAPI than Etherium Apps? I don't know much about Etherium but it sound like DASH Evolution without the currency features. Edit: Does Etherium make use of a second tier masternode network or how do they decentralise their Apps?
"Do you think DASH's Dapi could attract more developer than Etherium? Or is it easier to write DAPI than Etherium Apps? "
I think Ethereum have done a great job opening up the system to developers and getting them involved with all the tools and platforms they need to build DAPPs.
DAPI is a bit different because it's an interface not a language - e.g. with DAPPs you are writing code that runs within the ethereum network to perform specific tasks, whereas DAPI you are accessing the Dash network from external apps.
DAPI will definitely be easier to work with as a developer because it fits into existing standards, e.g. to DAPI enable a website for payment functions, you'll just include a Javascript library and call a few functions for decentralized access, whereas writing DAPPs there is a learning curve to learn a new language.
I think DAPI will attract more developers ultimately because it's about hooking decentralized Dash payments into the web and mobile systems so there are presumably a lot more applications to integrate DAPI than build internal programs for Ethereum although i don't know the Ethereum road map and this depends on DAPI getting traction (which is what we are all working for).
Regarding comparisons of Ethereum Dash, they are really for different things, I wrote about it upthread here:
https://bt.irlbtc.com/view/421615.msg13074815#msg13074815. Dash is the only crypto to add tiers on top of the single-tier model every other crypto uses though and I think that's the future because it lets you keep everything decentralized and build decentralized services on top like we are doing.
