Why not? You can level up with Zavala, the Gunsmith, and each of the vendors at all 4 destinations several times per day just by grinding. Ikora's gear is the same level as what these vendors offer, but you can only level up with her once per week. Having her inventory reset daily would both allow you to level up Vanguard Research at least once a day and bag one more Legendary Engram, and also give you more opportunities to replay the story missions.