HFT doesn't create any value. You take already created wealth and based on demand supply equations some one looses and some one gains. Think of it like a kilogram of potatoes changing 100 hands in a day during some make money and some lose depending on how the demand for potatoes is in a city. The HF traders don't actually do anything to grow potatoes or help the process of growing potatoes.
Higher liquidity and lower spreads give an investor more confidence in their investment. They always have the option of getting out of the investment and at a lower cost. More confidence in an investment means the investor will pay a premium over the same investment that is less liquid and has higher transaction costs.
This premium means companies shares are valued more in the secondary market. This also means that companies can fetch a higher valuation and thus raise more capital in the primary market. Both of these are a win for investors and the companies themselves.
What do huge chaotic fluctuations in the price that have no connection whatsoever to anything that actually effects the economically correct price for the item do for investor confidence?