Hard seltzers just taste like slightly flavoured sparkling water. About 100 cals per can (which range from 250ml to 330ml).
If you’re calorie conscious then worth a look if you still want a lighter drink that isn’t just straight vodka / gin. But don’t expect much in terms of taste, they’re all quite bland tbh.
I want to give a shout out to Jameson Orange. It’s described as a spirit drink and is 30%. Tastes lovely straight on some ice (almost like an old fashioned), or if you want a taller drink then with lemonade. Excellent value too as always with Jamesons. Lovely.