Many thanks for your replies.
Regarding the reply from @Fraxi: this is no argument not to add for all shop nodes the address. Sure, if there is e..g an office building where you have 10 different offices, 2 per floor, the building is cluttered with nodes and visually only few will be displayed. However, important is that the data is there, that Apps and data crawlers can get the info about that there is the particular shop.

My practical experience is that it is often impossible to divide a building into shapes to match house numbers. For example a shopping mall can house dozens of shops and for example in Germany these shops will have different house numbers, depending what street is the nearest to their location in the building. So the mall building can have a different street address than the shops inside. Then some areas have strange numbering history, like some cities use e.g. 7, 7A, 7B, while other use 7, 7B (so there is no 7A), some use 7A, 7B (there is no plain 7), some use "7" for the main building, but the shops inside all have numbers like "7/1" etc. There are so many different possibilities to number a shop. Some shops use for example post boxes, thus have a completely different address than their location would imply. So the most save and clear is to add the house number and also street to the shop. It does not harm but assures the data are available. I mean, no mapper is forced to add the address, but it makes sense to do so and instead of informing mappers about possible doubling of data, one should inform mappers that having the address for the shop is an advantage.