When to use miners / blasting charges instead of just dwarven warriors?

Topic. So I've been playing this game for (??????? hours) and still haven't quite worked out when to use miners vs miners with blasting charges vs just dwarf warriors. Here's how I understand them right now:

**Miners:**

\- no recruit building required, cheap; can get 4 miners for 3 dwarf warriors, 5 or 6 if you include the building costs.

\- half decent with a couple of xp points and the early +3/3 combat tech

\- great for garrisons and holding walls, with the advantages the defenders get. Especially against e.g. skaven

Great for a second cheap stack early on, or to flesh out a garrison.

**Miners with blasting charges:**

\- same as above but throws charges that will take out half a unit.

\- requires the same barracks and costs the same as dwarf warriors (well, about 5% cheaper)

The problem I have is you take out half the unit and the other half still beats you in melee, or they shoot you down before you get close. It might be great in a couple of niche cases, e.g. crowds of tightly packed skaven/gobbos, but otherwise you're better off with plain...

**Dwarf warriors:**

Miners but with shields and overall better stats; and they cost the same as blasting charge miners. Will hold 2-3x as long in melee. They won't do as much damage up front as the blasting charges, but they probably match or exceed their damage over the course of a match.

The only time I can think of when charges make sense is if you don't have any missile troops at all and enemies that clump up a lot. The explosions might also let them trade up decently well against chaos warriors/chosen.

How does everyone else use them?