Performance impact using load from cursor with remotefetch media type and LOB data.

Using the DATABASE option of the DECLARE CURSOR statement (also known as the remotefetch media type when using the Load API)
has some benefits over the nickname approach:

Performance
"Fetching of data using the remotefetch media type is tightly integrated within a load operation. 
There are fewer layers of transition to fetch a record compared to the nickname approach. 
Additionally, when source and target tables are distributed identically in a multi-partition database, 
the load utility can parallelize the fetching of data, which can further improve performance."
Link: https://www.ibm.com/docs/en/db2/11.5?topic=data-moving-using-cursor-file-type

The stated improvement in performance cannot always be achieved with the remotefetch media type approach when Lob data (CLOB/BLOB) is used.
The remotefetch media type load option does not support progressive streaming/Dynamic data format for lob data.
With larger lob content, progressive streaming can significantly reduce the number of network round trips and hence improve performance 
if network throughput is the bottleneck. 

In such a situation, it is advised to apply the data federation solution: declare a cursor on top of a nickname. 
Data federation does support progressive streaming.