multialgo not work anymore i think, i remember myriad coin, and it was doomed after the first pump, no one was interested anymore in buying it
So you are comparing it to myriad coin and digibyte being a multi algo what's wrong then with multi algo I remember Digibyte being a pow only coin I have long sold all my coins as I am more comfortable on POS coin as it is much easier without those expensive hardware..
as i said, they are dumped fast because the way the multi algo work, is not good, with many different difficulty and stuff like that, also there will be more miners, because there are more different algo to mine, this is equal to more dumping to me