An Interactive Broker username is required for Account Management and/or trading login. IB only allows 1 session to be established for trading login at any point in time for a single username, attempts to establish additional trading sessions would deactivate the other session.
The following image indicates that there is another active trading session:
Since one of the sessions is required for the robot to trade, another session is required whenever different trading is required, which requires the creation of the second username. Should the second trading session is not required, the creation of this second username is also not required, and the robot will still work accordingly.
However, since the robot actively maintains the trading session, the disadvantage of not creating second username is inflexibility when trading directly when other Interactive Broker facilities (Eg: Web Trader, Quick Trade, Trader Workstation, and IBKR Mobile App), where one of the session needs to be switched off first before establishing a new session.
Please refer to the following step-by-step guide on how to create a second user.
DISCLAIMER: The following screenshots are taken from Interactive Brokers website, provided only as a setup guidelines, and be changed from time to time, subjected to Interactive Brokers' discretion. AlgoMerchant is not responsible for any loss or damages caused by inaccuracy and misrepresentation of the information.