One motivation to use a dedicated datalog-like RDF-based inference
"language"
is truth maintenance: to be able to trace which triples were or may have
been inferred from which other triples,
so you can retract inferred triples upon deletion of explicit triples.
That is how GraphDB "pie" rules work (
https://graphdb.ontotext.com/documentation/10.8/reasoning.html).
They have various restrictions (no arithmetics, comparisons or negation)
that allow such "smooth deletion (
https://graphdb.ontotext.com/documentation/10.8/delete-optimisations.html).
In contrast, I am not aware of any work on traceability of triples derived
with SPARQL.
Even if you represent SPARQL in RDF, I think the traceability task is very
hard or even impossible.