It grows plentifully on the marshes round here but I rarely bother gathering it. If I want something that tastes like salty cabbage I'll just put more salt on my cabbage.
A lot of these 'gourmet' foods are just an excuse for ripping people off. It's useful to know what wild plants are edible but there really isn't much point in trying to grow them when you can have a plot full of 'proper' vegetables.
Of course, when society breaks down, supermarkets have all been looted and you're stuck on a salt marsh it might be handy to know what samphire actually looks like.
Hmmmm, our N Wales samphire tastes nothing like cabbage. It grows prolifically around here too, but I have limited mobility so leave the collecting to those who need to earn a few quid. It is not considered a gourmet food around here and when you can find it is cheap enough. I love the texture of lightly steamed samphire with butter and lemon, or with pasta, or in a salad, or a frittata............
Unfortunately we don't all have a plot for growing veggies, and will not be able to get one as long as we live here, so we grow what we can in our little garden and in pots on the drive and patio. So we grow what we really like and has a higher value.