Shiny shuppets are still around.
Answers
Well, unless they have a different form (male, female, other forms like for Burmy), I'd keep 1 normal and 1 shiny, and if the new shiny is better than the other, I'd keep the better one.
And then there's trading - a thing that may or may not be implemented. I could keep and trade for another, but unless it works for long range too, I would have a very low chance of actually finding someone to trade with anyway. I'm not one to approach people just because they play. In fact you're kind of an outcast around here if you play Pokemon GO anyway.
I've only spoken to one other player in my entire play time, and that was just because we happened to be raiding the same Bayleef. You'd expect people to gather at Legendary raids. Nope, they're rarely there and they're done by the time I get there as I do not know them.