Pink gin and water is also nice. 2 or 3 drops added to a ginger beer is one of my favourite very, very low alcohol drinks. Oh, and one of the several versions of rock shandy is 50/50 ginger ale and soda water, with a few drops of bitters.
A bit of searching and I've found culinary uses at this site

Bitters added to lemonade cuts some of the sweetness and makes a nice summer garden drink.

Is it any good for cleaning shower heads?

[pen] Only if it can dissolve the dead spiders.

That 'Shakespeare in Crescent' game we've just had brought to our notice was pretty good. We must do that again.

[Simons Mith] When I was a student, one of the drinks of choice at the time was a long vodka which consisted of a few drops of bitters smeared round a highball glass, ice, a shot of vodka, a dash of lime and topped up with soda water. A bit girly but very drinkable.

(nfras) How does that help achieve the main objective of student drinking which is to get pissed as quickly and cheaply as possible, then as now?

[INJ] I'll second anything in iambic pentameter!

[Rosie] Well, it's a cheap drink. No charge for bitters or soda, normally. When my dad was in the Royal Navy, it was traditional for midshipmen, and some other low-ranking officers, to drink pink gin, as all you paid for was the gin - hence it was the cheapest drink in the Officers' Mess - because midshipmen were so lowly paid.