With the German language settings, exporting a CSV file from a hosted feature layer by using the ArcGIS Web AppBuilder attribute table widget results in the point chosen for the decimal delimiter.

Solución alternativa

Open the CSV file in Excel via File > Open. This approach activates the Legacy Text Import Wizard, which allows the decimal and thousand separators for the import process to be changed. The Legacy Text Import Wizard can also be activated via File > Options > Data > Show legacy data import wizards: Here, select From Text (Legacy).

Pasos para reproducir