please answer the bold section about user experience design

When thinking about making changes to a product, based on your usability evaluation, it is important not to think about them as isolated improvements but in relation to each other. For example, consider the design recommendation for a mobile healthcare device: 'remove the help icon at the top of the display screen'. The reason for the suggestion, is it has been noted that when doing a usability evaluation it takes up too much real screen estate. Instead, the suggestion is to make it a hard-wired function, using one of the physical keys on the device. The rationale is that it will still maintain visibility of the help function at all times, but will also free up some display space.

Now think about what the consequences and trade-offs might be for the rest of the tasks the user has to do at the interface. In this case, dedicating a hard button to be the help button means one less key available for doing other tasks. Does this now mean that some tasks will need to be done by switching between modes, which wasn't the case before? Is this preferable? What is gained and lost in proposing this design change? Also think about why a particular way of doing something was designed like that in the first place (e.g. why was the help button put on the display?). What do you think the designer was up to and why did they make that decision? Did the designer have a choice, was it an arbitrary decision or was it a compromise?