I understand what you’re saying, but minutes, hours, days and weeks are fixed time periods that can be reduced to a number of seconds. Months and years are not which is why I did not include those in my earlier post.
Calculating the calendar date for an event that’s 365 days in the future needs to consider whether leap-time corrections need to be made during the period. We do that already for days with our standard calendar.
If someone says an event is in X days, they almost never mean a multiple of 86k seconds.
Really, I don't think you can reduce any of these to a specific number of seconds. If someone says an event is in 14 hours, the meaning is a lot closer to 14±½ * 3600 than it is to 14 * 3600.
If you say something will happen in three days, that's a big time window.