Summary:
Tools, especially weapons with their attribute modifiers hidden, have no attack indicator and deal very little attack damage. I think its a bug and unintentional, because "show_in_tooltip:false" not only hides the attribute modifier tooltip. I think it removes the base values of the item, which would be misleading if the intention was just to hide the tooltip.
Used Command:
/give @p diamond_sword[attribute_modifiers={modifiers:[],show_in_tooltip:false}] 1
Can confirm:
[media]