Not all Easy Access Savings accounts are equal. There may be better interest rates on other accounts, but there may also be factors that could still cause someone to pick Marcus.
For example, there may be a minimum opening balance that the saver cannot meet; there may be a restricted number of withdrawals allowed; withdrawals may not be ‘instant’.
I have a Marcus account, and while the 1.45% rate is a bonus (boom boom), my main reason for picking them over an alternative is that the money in that account would be my first port of call in the case of an emergency. When the bonus rate dropped from 1.5%, I looked at alternatives them and only one Easy Access Account had a rate higher than 1.45%, but it came with restrictions on withdrawing which is why I stuck with Marcus.
When the current bonus rate expires for me next year, I’ll shop around then - but it’s entirely possible that the correct decision for me will be sticking with Marcus.