Does praying in Buddhism have a different meaning or purpose as compared with religions with a creator God?
There are various points of view, depending substantially on the intent or state of mind of the person praying. I'll give you three of those points of view (POVs)
From the POV of the typical Christian, it absolutely has a different meaning. For example, in Catholic Christianity, prayer is "the uplifting of the heart and mind to God" (from the Catechism). Prayers are typically done to, through and "in the name of" Jesus, one of the three "persons" in the single tri-une God. God -- the personal, omnipresent, omniscient, omnipotent, omnibenevolent creator of everything -- is front and center of Christian prayer. If God is not front and center then best case it's not prayer, and worst case it may even be seen as downright dangerous and at risk from the influence of evil spirits. The primary purpose of Christian prayer is to bring the creature into union with the Creator (worship, praise, and also intercession are all components in that).
From the POV of the typical praying Buddhist, there is no such "fully featured" God, so again the meaning is clearly different. A common purpose is, as with meditation (which is very like, although not identical to, some contemplative forms of prayer), to help train the mind as part of the path to enlightenment.
However, finally, from my POV, I think it is hard to overlook the marked similarities between Christian prayer and Buddhist prayer and meditation, if you see past the difference created by the (excessive) anthropomorphizing of the concept of God. For example, the first time I participated in a chanting session in a Zen center, I was struck by how similar it felt to the many times in my childhood when I attended a Catholic Rosary service. Many Catholics, especially post Vatican 2, have tried to stress the importance of saying prayers in one's own language and in understanding and meaning the actual words. But via Zen, I came to see the value in the almost mantra-like quality of the high-speed Rosary, and of prayers and hymns in languages other than my own. This Latin, for example, is beautiful to my ears, and spiritually uplifting: https://www.youtube.com/watch?v=yYxyiUB1L0s
For another example, look at this extract from the Eighth Letter in the 17th Century "The Practice of the Presence of God" by Brother Lawrence of the Resurrection:
"...concentrate on keeping your mind in the presence of the Lord; if it
sometimes wanders and withdraws itself from Him, do not let it upset
you; confusion serves rather to distract the mind than to recollect
it; the will must bring it back calmly; if you persevere in this way,
God will have pity on you."
To me that bears a striking resemblance to instructions for Buddhist meditation. The main difference -- the idea of God -- is a difference only if, as I say, you take very literally the typical anthropomorphic view of "God". But if you see past that -- and surely whatever God is, if indeed God "is", then "he" is certainly not an old white dude with a long beard sitting up in the clouds -- my view is that there is often actually very little difference between Buddhist prayer and Christian prayer. This is, of course, a minority view! (Which doesn't, on the other hand, make it wrong.)