In addition to a listing of the 613 mitzvot, the Sefer Hamitzvot often includes scholarly discussions. Some examples: Elaboration on why certain Torah commandments are listed as independent mitzvot, while other seemingly single mitzvot are divided and listed as two; discussions regarding the penalties incurred for transgressing certain commandments; Talmudic proofs and even reconciliation between various rabbinic texts with regards to certain mitzvot.
This Sefer Hamitzvot Digest omits all these scholarly discussions, and includes only the information provided by Maimonides that pertains to the actual performance of each mitzvah.