Scientology churches do conduct worship services on Sundays but they're not like the conventional ones you'd expect. There's no deity that is the focus of all the praise, worship and prayers. Basically, services consist of Hubbard's writings being read and a time of reflection/discussion/fellowship afterwards. They can be quite short (roughly an hour, max).

The worship services were introduced at the time when Hubbard changed the direction of his Dianetics movement from "mental health" to "religion". They were created to seem more appealing and less threatening to a religiously-observant society. The services aren't essential to Scientology's operations; it's the courses and the auditing sessions because that's where the church's profits are made.