At first sight I read 'nuclear' instead of 'not clear' and I got scared. Then I though about it again and... sadly it could also be true.

Why? ICBMs can be launched and strike their targets within 15 minutes.

Even when slow, a relatively small, high altitude, no refueling, low heat signature plane with a small tactical weapon could be interesting for... reasons.

You underestimate the value and strategic purpose of second strike. https://en.wikipedia.org/wiki/Second_strike

By definition fired after you've already been hit with nuclear weapons.

Second strike is the deterrent measure to nuclear war, so why would improved second strike capability be a source of fear?