[kzzzznot]

The distinction in my mind is HFT is “worse” for market participants because of the front running of large orders between exchanges.

I’d argue this cross exchange arbitrage does still provide some value by keeping prices of securities across exchanges/the world in sync, despite being quite unfair and taking value from those putting in large orders.

Liquidity provided by algo market makers is also a service to market participants because they take risk to ensure there is always someone to buy or sell - this reduces volatility and risk for everyone.

Algo trading is also required for keeping ETFs in line their benchmarks, which is an entirely separate subject you could fill a book with.

So no, all algo trading is not the same thing, there are valid and productive uses of code rather than people shouting across a pit or running slips up and down roads to keep capital flowing through markets efficiently.