I am from Europe too, I collect graded coins.
Grading give one great advantage, there is little doubt on the condition of the coin.
This makes trading on the internet extremely easy, since you really need to have the coin in hand and study it with a magnifier to see the true quality of the coin.
Grading makes even more sense with brass coins, since the quality can vary depending on how the coin have been stored and handled.
For other coins types, e.g. Panda (which I also collect), they are mainly graded by PSGC, once they put the coin in the slap, then will they guarantee the authenticity of the coin, which is great, since it eliminates all the fakes, so you don't even need to consider make tests on the coin.
When that is said, grading is not always fair. You can find coins that are over or under graded.
Always buy the coin, not the slap. But a grading does commence an extra premium, at least the price for the grading (and round trip shipping), in return do you get an excellent storage medium and a professional opinion about the coin, which is useful if reselling.
I also have ungraded coins. So if you don't feel that a brass half MS66 is important to you, then I am sure you can find one in less quality for less, you can also be lucky to find one in equal or better quality for the same.
I like this coin, MS66 is a very good grade for this type of coin, if I was in the market for a brass half, then would I consider getting this one.
For reference, I sold a brass half MS65 for 1 BTC, less than a month ago, so DJ's price seams reasonable to me.