Are these a good or bad idea?
The good parts first of all include it can allow you to buy and sell crypto automatic meaning instead of you reading the data every day of the week to watch what's going on the bot should be sent if coded right the data into it so it makes the right buying or selling decision as much as possible for example if the crypto you buy at $20 that means if it goes down to $15 it should not sell it but if it goes up to like $25 then it could sell it for you then when it does down ahead it rebuys some then resell it when it gets higher again
The idea of this is to allow people money buy just using bot which does all the work for you and so you don't have to pay someone a lot of money to manage it all for you plus your bot can't go to sleep meaning it is will not after 16 hours work need to sleep it can work 24/7 for why these became popular in some places so far. https://www.epintoken.com/2022/09/ethereum-eth-number-2-to-bitcoin.html
The bad idea mostly comes from it is being coded wrong for example if it can't tell the difference between price increase vs price decrease it could make big problems for investors overall and in extreme cases which could make them lose money. or go into debt in extreme cases so if you want to buy one make sure it is coded as well as possible and test it before you try any serious work with it overall which can be good way to stop you losing money overall.