Huawei mate 20 per single / dual sim?

The question is for those who really know and do not think they know it

I have in mind in the next 3 months to buy the mate 20 per. Until now I always wanted the dual sim version, but then I thought to myself: Why do I actually want the dual version, if I only use a sim card and a sd card anyway? (i know sd card will not work on the cellphone because you are selling your own or something)

So I would like to know where the difference of the two versions is, except that I can use a sim sim card? Is there any? And if not, why is the single sim so much cheaper?

There's no other difference.

Both cost the same.

https://geizhals.de/...mp=1907976

Oh, the ones I saw on ebay were probably needed. Why should one then buy the single sim mobile phone?