This is a bad thing masquerading as a good thing. They will be cutting staff/hours to control labor costs. No company is going to increase labor costs by a third out of their profits, it just doesn't work that way. Full time will be cut to part time. Part time hours will be reduced. Number of positions will be reduced.
If you are making $10/hour now, full time you'll be lucky to get 28 hours at $15/hour for roughly the same paycheck.
But with your new free time, you can look for another part time job.
Don't forget that most part-time workers no longer qualify for benefits, insurance or other type perks.
Not always the case, but yes, this is very possible. Sometimes a company may have a sizable employee turnover and may want to raise the minimum wage just to keep the workers they train happy and willing to stay loyal. I guess time will tell in this case.