1) Depends on the risk assessment each of us does.

2) Security <> Convenience

I invest with a couple of different brokers. Some require only username+password. Some have the extra SMS/2FA. There is one where I get an automated phone-call and I have to answer, and type the digits shown on the screen. Every 1st of the month I do 'the rounds' in every account I have (bank, broker, cash) and write down on a spreadsheet my 'net worth' so I can track progress, forecast, see with a nice line how much up or down it goes, etc. (friendly suggestion - all people should be doing that); so it amuses me to see so many different authentication mechanisms across the Finance world.

Check out beancount and plaintext accounting. So much better than spreadsheets, IMO.