US approves transfer of 125 long-range missiles, 100 Patriots from Germany to Ukraine, NYT reports

Well, you need the missiles to use the batteries. I think their point is that a shahed will be blown out of the sky regardless of what SAM missile hits it, and patriots are on the expensive side of SAM missiles. In other words, 100 missiles is enough to shoot down, at most, 100 shaheds.

The advantage of patriots is their high accuracy and ability to engage several targets simultaneously. Therefore, they're probably kept back to take out targets that get passed other AA systems, and to protect more critical infrastructure. That way you don't spend them on shaheds, which can be taken out by pretty much any AA, but save those 100 missiles for when they're really needed.

When you look at it that way, these 100 missiles will probably stop close to 100 targets that otherwise would have gotten through, and that's quite a lot.