Whenever you set a global hit or time-limit for public links, the user who creates the public link is unaware of that. Even worse: They can still set the public link to expire in (i.e.) 50 days, even when the global limit is set to 10 days. The global limit is still applied and the user thinks it can be used for 50 days, although it will be unavailable after 10 days, because of the global limit.
Please make the maximum limit the user can choose equal to the global setting.