The value axis labels can also use "Integer Only" if you don't want decimals to be displayed on the axis. The formatting will still be used for the hover text though.
This config uses Integer only but shows up to 4 decimal places in the hover text
This config shows when "Integer Only" is disabled while showing 4 decimal places in hover text.
This config shows when I only want to see one decimal place and integer only is disabled.
Hover text off, but using specific formatting for labels on the chart.
I hope this helps. If you have a different use case or requirement, can you show a screenshot of the issue?