It could be used as an excuse why more costly options to avoid pain and suffering in old people might not be covered by insurance anymore.
People could be talked into it for various reasons.
Canada is a good example of a country where I think the base to make it work in a positive way is given. Their insurance covers a lot of treatments for basically everyone. The country cares about its citizens in a way that makes you believe they won't use euthanasia as a cop out to avoid paying for medical care.
If these circumstances are not given, euthanasia can easily be seen as an easy way to get rid of people who are too expensive for society or too cumbersome to take care of.