Lee, think of SSM as a way to label an approach you want to take to research a 'messy' subject where you cannot agree to approach the research through any hard and fast methods ie statistics, maths.
SSM gives you the freedom to 'wander around' your specific subject and qualify topics as they are uncovered. Using Rich Pictures to justify/qualify your findings. It also gives the reader of your research a quick and precise understanding of your research method. All the semantics about Weltanshauungen I would discard as 'noise' by researchers poorly acquinted with the German language. Think of using what Checkland suggests as reasonable when you wish to formulate a finding from different points of views when describing a sub-topic.