Hey Kalin79-

Thanks for your continued interest.  We considered the possibility of a CPU-only algorithm like CryptoNight, but felt that widespread adoption of bitcoinR mining would be best accomplished by staying with SHA-256 for three reasons:

1.  Few individuals who mine with CPUs know much about hashing algorithms and are unlikely to prefer one over another.  They simply download and install a miner and await a block discovery.  The somewhat hesitant adoption of this in early April reinforced the case that most people weren't able to understand it.  We knew then we'd made the right decision using SHA-256 to eventually approach veteran miners.

2.  For those individuals who are veteran miners, we posited that they likely have access to equipment that they previously used to mine BTC and were unable to sell / liquidate via eBay or Amazon.  Due to the individually held backlog of SHA-256 mining equipment we envisioned a veteran mining cohort that could get going faster in the mining of XBR by redeploying this unused / obsolete BTC mining inventory.

3.  A substantial aggregate network hashpower, evenly spread over a great number of individuals or entities has a better chance of decreasing the probability of a 51% attack.

Once serious miners can get their heads around the hashpower and difficulty going up and up, they can assess what individual hashpower requirements will be necessary to mine a block individually or as part of a pool.  Smart miners will make an attempt to jump the queue at a discount by going to a place like eBay, Craigslist, Ganji, Xianyu and pick up a used Antminer S9 for less than $200 USD which should, at present, be adequate to mine XBR.  Some vendors on Alibaba will give miners a discount (<$100 each) if they buy massive quantities of 10 or more.

CPU mining of XBR is now largely a lost cause I'm afraid.  I updated and uploaded v.29 of the Official Whitepaper today to reflect this.