Per Brian Seifert of The Verge:
The big new feature this year is an always-on display option so you can see the time without having to move your wrist, something that has been asked for since the Apple Watch first debuted in 2015.
Apple is going to sell boatloads of Series 5 watches to upgraders, due to the new, always-on display. That is the one feature—and pretty much the only feature—I wish my Apple Watch 4 had.
Apple is also permanently dropping the price of the Series 3 to $199, matching the lowest sale price on that model we’ve seen
Apple will also sell boatloads of Series 3 watches at the new, lower price, too. Apple is wisely going down-market with their older watch models, just like they do with the older iPhone models.