It's a little strange that type conversions are nodes themselves. Some consequences of this are:

• Type conversions show up in the context menu, when the user of an application should never have to worry about it (the conversion node is inserted automatically)
• Diagrams are bigger because of the extra full-fledged node
• Moving nodes around becomes harder, because the full-fledged node isn't moved with the connection

I think it would be useful to have an "implicit" type conversion. These

• Wouldn't show up in the context menu
• Would be part of the connection. Either some kind of label on the connection, or a "node" which is fully part of the connection. The ideal is for this "node" or label to be rather small to reduce clutter.