On mSecure 5 (Mac), secure fields can only be copied. To reveal contents it is necessary to open the item and edit it.
Some use cases require you to type the information and copy / paste is not possible. Eg some Credit Card fields (CCV etc).
On the iPhone version it is possible to reveal or copy the field when the field has focus / highlighted.
I can see a tooltip in this Mac screenshot.
I can't see any tooltips for any UI gadgets in 126.96.36.199 on Win 10 Pro 1709.
There is no tooltip at this moment for some of the options in mSecure 5 on Windows. However, the icon is the same on Windows: