The Emercoin development team has decided to combine the production of both Bitcoin and Emercoin with a vision to significantly increase the trust and reliability of the Emercoin network. Due to the algorithm used to produce both Bitcoin and Emercoin being a common factor, this is a sound and achievable technical decision.
The members that comprise the Emercoin team believe merged mining will signal an increase in network difficulty by 500 times or more for the Emercoin blockchain. This increase in network mining power will help to increase the Emercoin network's credibility, which is a critical asset in today's cryptocurrency world. In short visibility + activity = legitimacy in the public eye. To this day, visibility has been the primary aspect holding back the adoption of Emercoin by the general public.
This change will also benefit miners in an economic sense. Currently with the SHA-256 algorithm, if a Bitcoin miner were to "mine" Emercoin or vice versa, the miner would need to divert power away from one blockchain or the other. The addition of merged mining will allow miners to produce both Bitcoin and Emercoin in harmony, without losing the benfit of income from either blockchain.
The increase in network stability was a major factor in this decision. The most important piece, the growth of the Emercoin [Suspicious link removed]plexity, is also a sign of the growth of trust in Emercoin. As complexity on the blockchain increases, the likelihood and effectiveness of network attacks or deficiencies decreases tremendously.
The positive effects this change will have are clear. What are the negative effects? The team has confidence that there are virtually none. The fact that the block reward will decrease with a higher complexity/difficulty is a negligible effect, since an enormous increase in difficulty of 10,000 times would only bring about a reward drop of approximately a factor of 10. The Bitcoins a miner will receive will offset any decrease in Emercoin reward per block.
As stated before, this change is coming about to help bring trust and reliability to Emercoin. Where trust exists, further development, innovation, and success will follow.
Source:
http://emercoin.com/2016-06-16-Emercoin_Team_Announces_Merged_Mining