Lots of people don't like to dangle a motif - my friend went to dinner the other night wearing three in a row that way. For her it wasn't about buying a necklace or not, she just LOVES the idea that the bracelet can do double duty and will not shorten it so that she has the option. I wouldn't dangle a motif, but I do have a five on my list which I will never shorten either; I may wear it as a bracelet on occasion but will also use it as an extender for my 10.
I personally DO like wearing two bracelets as a necklace. Lengthwise it is fine on me. The only trick is to wear a blouse with a collar; between my hair and the neckline, no one is going to see more than two or three motifs anyway, much less a clasp (I'm not exactly swinging my head around either, so it doesn't shift much). I have done this in the past and was very happy with this option.
This is a cowl neck sweater with two 5s

This is a 10, but you can see with a blouse you're not seeing many motifs, anyway:

I personally DO like wearing two bracelets as a necklace. Lengthwise it is fine on me. The only trick is to wear a blouse with a collar; between my hair and the neckline, no one is going to see more than two or three motifs anyway, much less a clasp (I'm not exactly swinging my head around either, so it doesn't shift much). I have done this in the past and was very happy with this option.
This is a cowl neck sweater with two 5s

This is a 10, but you can see with a blouse you're not seeing many motifs, anyway:
