First, an investor holding VCIT can lower the risk of their portfolio by adding SGOV without sacrificing much yield.

Source: https://seekingalpha.com/article/4611907-sgov-ultra-safe-high-yield-etf-belongs-in-most-portfolios?source=feed_all_articles

In short, then, if one selects VCIT over VGIT, one is rewarded with roughly an additional 1% in current income, but at the "cost" of slightly higher interest rate risk and a fair amount of additional credit risk.

Source: https://seekingalpha.com/article/4577577-vgit-comparing-conservative-option-2-alternatives?source=feed_all_articles