I think v18 came out with the "blocks" functionality. There is also a "smart" connector and other grid tools.
Basically, SE tried to combine the best of Visio with some standard ACAD tools (since that is what the market is mostly using for schematics in the MCAD world).
SE v19, which I currently have loaded and is the latest release, has 18 categories of electrical symbols. There are numerous blocks within each category.
So, yes there are people doing schematics in SE, even before these new tools were introduced. And, yes, there are ready made symbols.
With V18, the concept of "Blocks" was introduced which parallels AutoCAD's Block functionality and can in fact use any existing AutoCAD Block libraries. Symbols also still exist, but where blocks are individual sets of user defined geometry and several defined blocks can be stored within a single Draft file (the file is the library container), a Symbol is comprised of whatever graphics exist in a single Draft file, so for each symbol you create, it is saved as a Draft file. Symbols do have some options that the Blocks do not. A symbol can be placed as graphics (no remeberance of the fact that it was a symbol), linked (associative to the original definition. Think Write Blocks from ACAD), embedded (each instance in the drawing can be individually edited without affecting the others in that drawing), and shared embedded (editing one in the drawing affects all others in the drawing), or as a block. Blocks work like Symbols placed using the "shared embed" option so editing one block in the drawing makes all other update to match.
