What if you wanted to select "top 100 most expensive products" or number of products between $0.01 and $10, $10.01 and $100, $100.01 and $1000? Sure you could do a full table scan on your products table on both queries but an index on price would speed both queries up a lot if you have a lot of products. Of course you have to determine if the index would be used enough to make up for the extra time on index update when the price changes or products are added or deleted.
I used DBeaver (community edition) before Datagrip and I would have to give the nod to datagrip overall. I wouldn't have even tried it if I did not have the etbrains all product pack. DBeaver is great, don't get me wrong, but Datagrip just seems a lot more polished overall and the settings and the UI just seem more intuitive to me.