I don't know if double mining negatively affects bitcoin mining, but if it does not affect these coins can be mined and stored in the long term (at least in theory), for example ELA is now $0.8 while its ATH was about $80, also SYS is now priced 0.09 while its ATH was around $1.
I know these coins don't necessarily have to get their ATH back but my point is they are not profitable right now but they could be profitable in the long run.
Merged mining has no negative effect on
BTC mining, it's just a negligible tiny bit of data stored in the actual bitcoin block and doesn't change how much a miner earns in
BTC, for every BTC you mine you get (2 NMC, 5 SYS, 0.1 EMC, 0.8 ELA) from Viabtc, so ya, if they get to their ATH, that's about a $100-120$ extra on top of every 1 BTC you mine, I don't think anyone would refuse to get them even if they wroth 10$ in total, "free money" is good.
