Antiques are generally meant to be used as Monica said:
To accentuate the detail and shading in carved and tooled leathers. Usually, you'd finish your tooling, possibly dye, apply a clear finish as a resist or an actual resist product selectively and then put the antique on thickly rubbing it into nooks and crannies and excess wiped off to allow the antique to remain behind in the low spots to dry there. A final finish is applied after all is dry.
That being said, the Eco Flo gel probably makes a better leather stain than it does antique. It tends to discolor resist too much for my taste. I also seem to have a hard time sealing the eco flo gel to prevent dye ruboff with wetness / sweat. I've swtched to Fiebings antique pastes for my antiquing, but the gel still has it's place.
In the end, it's all about what you like and what works for you!
Hope that helps
Bill