When selecting assets for a portfolio the underlying cost associated with those assets needs to be considered. You should only undertake expense if it is justified by receiving added “value”. In saying this selecting the cheapest asset is not a sure way to maximise the value of your portfolio especially in the short and medium term. It is widely accepted that diversification is good for a portfolio.
To be truly diversified you need to own assets that have low correlation. To do this you need to own different assets and have different strategies with the assets you can get exposure to. The reality is getting some assets or strategies is more expensive than say an index share portfolio.
Whilst when comparing apples with apples the cheaper the investment cost the better those who manage this issue well will get far superior outcomes for their clients as they will be able to stay on their financial journey with a much smoother ride.