They had to move off Tartt. Dude was injured 10 games a season. And when he played he was solid but not anything beyond that. We can do worse than him, but the lack of availability really stunk.
SS is the cheapest defensive position to fill, especially if you're a Box Safety. When you do a lot of cover looks and disguises, you do need a safety who can cover. Huf, Odum etc aren't long term plays imo but this FO doesn't ever want to spend on a SS. And playing a FS who can cover at SS is usually wasteful.
Hell, I remember Chiefs picking up Honeybadger for peanuts.