If you say that something is better than nothing, you mean that it is not what is required, but that it is better to have that thing than to have nothing at all.
E.g. After all, 15 minutes of exercise is better than nothing.
https://www.collinsdictionary.com/dictionary/english/to-be-better-than-nothing
Après tout, 15 minutes d’exercice valent mieux que rien.
qqch vaut mieux que rien est-il utilisé en français comme sth is better than nothing en anglais ?