Vaults are similar to Astroport farms. It provides liquidity to Astroport, and investors can earn farm token rewards (ASTRO, VKR). However, to deposit to Spectrum Vaults, investors do not need to collect and re-invest reward manually, Spectrum will perform Auto-compound for you.
In this strategy, farm token reward (ASTRO, VKR) will be harvested and optimally swap to pair assets and then reinvest into the pool again. This will result in growing LP over time. With more LP, farm will reward more token reward. With this effect, this strategy gives the highest possible APR.