Do they want to be worshiped or do humans just want to worship them? Why do they need to be worshiped?
Do they need it? That would depend on the deity, I suppose. ... and semantics of course. Do they absolutely need it? Else they cease to be? No, that's not how I understand it. But, it, the worship, is needed on condition, if the deity ( or the aspirant ) desires to have an encounter with each other.
The act of worship is a method for having an encounter with them. It's a rather complicated topic , but, trying to be brief, these "beings" exist in a realm of absolute truth. In order to "exist" "there" with them, the mind must hold an absolutely true conception of this "other" "being" or "beings". Otherwise, the mind is immediately rejected from that realm. Nothing can exist there which is not absolutely true. That includes thoughts.
This poses a dilemma, because these others are so very very different from us, that it is almost completely impossible to develop an absolutely true conception of them in the mind's eye. It's a long, painful, lonely road, but I'm told it's highly rewarding on completion. The Hindu, I believe are the best resource for this.
A much much easier way to consistently produce an absolutely true conception of these other "beings" is not intellectual. It's emotive. For each of these other "beings" ( assuming they exist ), there is one and only one absolutely true conception of them which can be conjured in the mind's eye. However, there are nearly infinite ways to
feel about them, to
feel about what they are doing ( present progressive tense ). Each and every one of those nearly infinite ways is almost always absolutely true. If the aspirant is educated on the "doings" of that particular other "being".
That's where prayer / worship comes in. The worship or prayer or ritual intends to cultivate an emotive response within the aspirant which is very likely to be absolutely true for the one or ones which are being invoked/evoked.
I hope this answers your question.
Best wishes,