The role of the 'architect' is hard to describe as there are many varieties out there - the common denominator being that it may include all stages in the creation process part from doing the actual implementation. In small projects or organisations, the architect will do everything from clearifying functionality with system owner to describing models for software implementation and technical infrastructure. In larger organisations you may have a huge stack of architects, doing enterprise-, functional, software or infrastructure architecture.
The role of an architect in the original sense was that of drawing buildings, landscaping, designing interiors, planning cities and so on. The two main aspects here is aesthetics and function, in short: To design an area that has the desired qualities for humans to be and live in. Their knowledge isn't 100% limited to the visible part of the design - they may need knowledge also on more technical aspects of what they're designing. The architect wanting to create a building with large wooden roof beams, no visible posts and transparent walls may need to clarify the options and/or costs of this concept with someone with engineering / entrepreneur skills. Also, when drawing e.g. an airport, the architect needs to acquire knowledge on the domain to design a functional one. The latter is valid for a system architect as well - there will be need for collecting knowledge from adjacent areas.
The big difference is in what's the main field of work: Design of underlying structures or surface design ? I believe the role 'system arhitect' more closely resembles the role of the 'engineer' in the construction field... and that the traditional 'architect' in the field of construction reminds more of the role of a 'designer', especially 'visual designer'.
But I totally agree - 'Architect' sounds much cooler than 'Engineer'... more artistic and interesting, in a way...