Why do you think that XSpec is more anonymous than BitcoinZ or ZCash? Just because it uses Tor by default? You can do this by yourself if you want.
I just stated at the start of the video why BitcoinZ is better than Bitcoin.
First Bitcoin becamed centralized in mining, because you can no longer mine it effectively or with any reward with a normal computer.
Secondly transactions sender, receiver and ammount are visible to everyone, making in this case much easier for an attacker to track a specific address and find the specific person.
Third the cost of a Bitcoin transaction was a couple of days ago 20$ and it takes more than an hour to validate the transaction on the blockchain and to arrive at the receiver, making it infeasible for buying and selling ordinary stuff on a market. Also the number of transactions per second is quite limited.
And last the Bitcoin community seems more short term profit oriented in contrast with Ethereum for example, where the community develops software in its name "smart contracts" on top of the Blockchain, enabling a huge variety of applications, not just store of value.
I heard that BitcoinZ community wants to develop smart contracts as well.
I heard that Bitcoin wants to develop as well "Lighting network", but honestly in the current situation I don't see Bitcoin to be the top Cryptocoin in the next years.
Remember that Facebook wasn't the first social network, Google wasn't the first search engine, but they brought new stuff, technology and opportunities which made them the best on the market, at least for a while.