The salient distinction is that mining influence in Bitcoin has nothing to do with how many tokens you own. And mining expenditure is ongoing whereas staked masternodes are only deposited once.
We've already explained this before. I am not going to explain again why staking is not secure.
Mining influence in DASH has nothing to do with how many tokens you own either. Miners govern the coin in exactly the same way as other PoW coins - they can fork a chain at any time.
Masternodes/DGBB create an additional governance layer, providing, right now, funds for all sorts of beneficial projects directly from the blockchain.
Nobody is saying it's perfect, finished or a replacement for mining. It is, however, a good working solution to the governance issues and decision making malaise that stunt the growth of other coins.
Masternodes can corrupt the security of the InstantX and the anonymity.
Evolution is building more corruptible features on masternodes.
Masternodes concentrate the coin supply to those who own the masternodes by paying them a dividend (up to 50% per annum according a chart that was on the Dash website last year), and the masternode has no significant ongoing cost, as the stake deposit is only made once.
The decentralization of the mining is irrelevant when the coin supply is largely controlled by those who instamined and have been concentrating their percentage of the coin supply, thus they can force any protocol change they want, because ultimately it is payers who control which protocol they sign their transactions to.
I don't have time to get in a detailed debate with you, but rest assured I can destroy all your arguments when I am ready to. That time is coming... just wait...