what benefits do algos have? Are they just strategies that the computer watches then buys/sells or can you have them run the strategy without buying or selling? Do they look for patterns through multiple tfs/instruments? How often does an algo profit.. as much as a person or more?
It is really whatever you want.
It might help to think about it as - to achieve a fully automated trading you need (a) very formally defined strategy (b) software to be able to execute it live.
"a" is normally what is called an algo. You can have just "a" and trade of its' recommendations.
Benefits of "a" is an ability to backtest and see in advance how it would perform in different market conditions. If you run it over 10-30 years of data over multiple market cycles you will get an accelerated education on what you will likely to face.
What you normally don't know is what type of market we will be having in the future but it is likely on of the ones that already happened. You could define separate strategy which thrive under different market condition and doesn't loose too much while waiting for it, then combine them and aim to make money in most markets.
Benefits of "b", as others pointed out is ability to not stare at the screen all day waiting for your setup and not having your emotions interfere, as computer will do exactly what you told it to do.
Here a link to my journal where I talk in details about this stuff