Retirement accounts
Stock investments
Credit cards
Payments from house to cars
Life insurance
Auto payments
Lines of credit
3 bank accounts doesn’t simplify anything so it just makes the chance for problems higher...
I’d say if everyone isn’t aware of all three accounts then, yes... my money is on major problems in your future... if everyone is fully aware with PWs etc I’m sure it’s possible to avoid problems... but it is a ticking time bomb that may or may not splode