Pro: why should I play a druid? To have fun.
Druids are very versatile. They can do damage (call lightning!) and they can heal. They can engage in melee combat (Circle of the Moon Druids are very good at this), and they can cast spells.
Iconically, when you are up against monsters in full plate armor, there's heat metal. Dinner, freshly cooked, when you turn into animal shape and feel hungry.
All druids are full spell casters with a full spell casting progression. Druids can cast, at high levels, spells like true resurrection. That brings party members back from the dead.
Wild shape: from level 2 to 20, the druid can transform into beasts, and take on the advantages and characteristics of those beasts. (Great hearing as a wolf, walking on ceilings as a giant spider, constrict enemies as a big snake, etcetera). By 8th level, wild shape allows for both swimming and flying animals for wild shape: you can go anywhere.
A favorite spell is polymorph: turn into a T Rex and terrorize your enemies! Go all King Kong; turn into a giant ape! For even more fun, turn your hobbit ally into a T Rex and watch him run amok!
At high levels, there's urban renewal; Earthquake. (I saw that spell completely wreck a Frost Giant's stronghold)
A variety of nature based spells, like entangle or grasping vine, let the Druid harness the power of nature to help your party defeat their enemies; slowed or constrained enemies are easier to beat in combat. Numerous earth, wind, fire, and storm spells are at your command. If you have access to Xanathar's Guide to Everything, there are even more spells available.
You can cast every single druid spell in the book. Your only difficult choice is "which one do I prepare today?" Nice problem to have. (Clerics and Paladins run into that decision requirement also).
Oh, and talking to animals. Got a Dr Doolittle itch waiting to be scratched?
Druids have spells that let them talk to animals.
The highest level druid I got to play was 10th level: I turned into air and earth elementals. Massive fun.
Con: Why should I not play a druid?
You should not play a druid if you don't want to have fun, or, if you want to find fun with a different class.
I suggest that you open the PHB and review each and every druid spell in the book. Then, think about how you can use them.