I'm not trying to be inflammatory here, I just simply cant wrap my head around why someone would play a cleric other than filling the healing role in a party. I understand domains help them specialize and give them interesting options, but why choose a cleric with a certain domain over a class that functions the same way, just better?
If you want to be a capable warrior with divine magic, go paladin.
If you want to be a capable caster, why go light domain cleric over, say, warlock/sorcerer/wizard?
If you want to be a gish, like tempest or war domain clerics, why not just go eldritch knight?
I look forward to being enlightened and perhaps converted to actually trying a cleric one of these days.
Hiya!
I thought about this, and I know you are expecting a "mechanical reason" because...uh... reasons?
Every time I decided to play a Cleric (ok, so there haven't been many; I DM 99% of the time), there was one, single, underlaying factor that I
think I distilled it all down to: Flavour.
Honestly don't give a flying fig about mechanics. They don't make any difference as to if
I enjoy playing a PC. But, to answer your question more specifically... I play clerics because I think of a character "look/vibe/feeling". Typically I tend towards real earth-based religions of old (Egyptian, Norse, American Indian, Chinese, Sumerian, etc) because I have a stereotypical 'idea' about how, say, a Cleric of Raven (American Indian)...with my "Sacred Bundle" of rocks, bones, herbs, dried flowers, dirt, etc, and my feathers/bones/semi-precious stones adorning my person as jewelry, maybe tattoos or body paint. Then I move on to personality; quirks, like a fascination with shiny stuff and acquiring "comforting necessities of life" and building a sort of "nest" over time in any location he/she finds his/herself (e.g., the first night of a room at the inn might just have my dreamcatcher hanging up; the second night has a religious tapestry weaving hanging on the wall; the third sees a couple of fluffy fur rugs; the fourth night and I have a replaced the blankets/sheets with my own; in another week or two...it's no longer a "room at the inn"...it's now "my sacred nest of safety"

).
So...that's why. Flavour. Look. Feel.
Mechanics, abilities, spells....? ...ppffft...whatever, I don't care. Those are just "extras" or "after thoughts".
^_^
Paul L. Ming