I would hope that BTM does not go down the path of merged mining. A coin will only have value if people are willing to expend resources to acquire it. As soon as you get them for free - well that is what they are worth. The recent fork of DOGE is a good example. Before merge mining the coin was worth 41 sat. Now the nethash has multiplied by a factor of over 6 from 60 odd gh/s to 373 gh/s yet the coin is still only worth 41 sat. The is an effective over 80% devaluation of the coin.
People will merge mine coins like Dogecoin with Bitmark if they'd like to. With Bitmark having the actual PoW being done for it. I expect to see people mining BTM and DOGE together fairly soon.