When you use the word “epilepsy” the whole negative history of the disease comes into play. However, if you say “seizure disorder” it sounds more clinical and is detached from the images tied up with epilepsy. There are a of of myths associated with epilepsy, but not necessarily with the term seizure disorder.
And even among cases of epilepsy there are great differences. Different types of epilepsy include generalized or partial epilepsy, and idiopathic or symptomatic epilepsy. And then there are different types of seizures, such as grand mal, absence, myoclonic, clonic, tonic, and atonic seizures. There are hundreds of epilepsy syndromes. I have noted that on forums dedicated to epilepsy folks tend to use the name of their syndrome rather than the word epilepsy.
And, yes, there are indeed seizure disorders that are not epilepsy.
It may be something like using the term Hanson’s Disease instead of the word leprosy. You shed the historical and cultural connotations associated with the older term.