Transistors and FETs, wrapping my head around them

[Marco]

those beast are rare as they are not very practical ...

They seem nice for protecting high impedance inputs which might be exposed to high voltages, with one or two depletion mode MOSFETs (depending on whether the current is bipolar or not) and a resistor you have a self powered current clamp to combine with a TVS diode for input protection.

Is there an inherently better solution I'm missing?

[c4757p]

BJTs are current-driven - no base-emitter current equals no current whatsoever... And base is low impedance. So why is it that in most circuits I see pull-up or pull-down resistors on BJT bases? I thought the only time you need a pull-up or pull-down is if you have a high impedance, voltage-driven input to prevent excessive weirdness from happening... But if you left a BJT base dangling, it would just cut current and close the transistor...

...or wouldn't it?

Additionally, because they are actually voltage-driven as mentioned above, they can remain turned on for a short period of time by charge held in the base, just like a MOSFET (only not as dramatic). A pull-down resistor can help them turn off faster, and the effect of that resistor setting a lower bias point even in saturated switching applications can limit the amount of charge put into the base in the first place.