Already trade expectancy for intraday is NEGATIVE for Nifty Options.
Introducing algo adds up to trades which means more trades in a negative expectancy space.
Adding algo trades is like increasing your pond size but fishes count never change!
Usually price moves in unexpected spikes in day frame
'Algo fishing net' is usually a rigid fishing net that can capture only extremely small ways of market price behavior (no algos can capture fat tail, blackswan moves).
so the 'algo fishing net' is guaranteed to severely damage your acc. unless you are employee of 'Renaissance technologies' (where all employees are Ph.Ds in physicsMath and a quant) !
For zerodha its a nice selling point to put on a bulletpoint for presentations on 'why zerodha?'
Setting aside Zerodha's marketing regarding algo trading, I think many guys here are confusing algo trading with high frequency trading(HFT).
HFT is a special form of algo trading that requires complex mathematical formulae, software, co location server etc etc. Algo trading means simple automation of trading activities like entry, SL, trail stop exit etc. You can just automate a moving average cross over system and it will become a algo trading system.
Whether one has a profitable strategy and whether it can be fully automated is a different thing. But algo trading does not necessarily have to be high frequency trading.
For example algo trading can be done even on daily chart. Many mutual funds and pension funds use algo trading and they dont do day trading. One of the primary reason these mutual funds/pension funds do algo trading is to break their large orders into smaller orders.