There mainly 2 patterns for incrementally loading data for facts.
1. Load new records to staging
2. Truncate any of these rows from Fact Sales
3. Insert records from staging
This is good as it saves having to update records that have changed.
The other pattern :
1. Load to staging
2. Do a MERGE into fact to upload New/Changed records
Of course it relies on being able to get new/updated rows from the source into staging.
I've mostly got experience of the latter. My question is when would pattern 1 be suitable over the merge?