I do see the real difference between these two adjectives? Does so want to help me ?
In everyday speech, colloquially, 'useless' and 'pointless' are considered and used synonymously and interchangeably - and there is something to it. You don't have to worry about using both terms synonymously in everyday speech, because 'pointless' is often interpreted as 'useless' (and vice versa). In this regard I would say both words mean the same.
Nevertheless, there is a subtlety if you look closer:
I can very well be [b]useless[/b] (=to no avail) to ask your question here, in case there is nobody around here in this forum who answers the question. Then 'it's no use' to pose the question in the first place because nobody will answer it.
But your question itself is not [b]pointless[/b] (=it makes sense), that is, asking the question in general is not at all pointless. A pointless question would be, for example: "How does he colour green smell?". This question doesn't make sense, the question is absurd.
I would paraphrase both terms as following:
useless - sth. is to no avail, it won't bring about any useful results pointless - sth. doesn't make sense, sth. is absurd
Hope this explanation is neither useless nor pointless.