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First about bot manipulating price, does this happen in centralized market or also decentralized market?
Bots are preprogrammed to create predictions, always rely on your specific decision. Making a good moves is dependent on how you initiate a smarter trades, when market starts to increase a potential gains. Doing it physically is much better than virtual strategies.
There are also bots that you can use to execute your trades, not only to predict price movements. But they aren't perfect, they are just faster but not smarter than human.