Why filler ON wallpaper behind baseboard? Built in 2008

[Enselic]

I live on the ground floor in a condominium in a house that was built around 2008.
When I remove the baseboards in the bedroom, you can see that filler (I think it is) is applied at the bottom on top of the wallpaper. Here is a picture:



Anyone have any idea why this has been done?
I have problems with silverfish and am looking for moisture, could I be onto something?

 

[Fotografen]

Irregularities that have been wallpapered over "because you can't see them behind the skirting board" which then had to be adjusted to make the skirting board sit straight?

 

[per-o]

Leveling compound from the floor that splashed up a bit..?