A GPU-hour does not buy the same machine on every row
The $ / GPU-hour column divides a machine's price by its GPU count, which makes a single-GPU PCIe box and a node in a training cluster look like the same unit. They are not.
AWS p5.48xlarge, Azure ND96isr_H100_v5 and OCI BM.GPU.H100.8 are 8-GPU SXM nodes: the GPUs are linked by NVLink inside the box and the box has 400–3,200 Gbps of RDMA / InfiniBand fabric to its neighbours. OVHcloud's H100 flavors are PCIe cards in 1, 2 or 4-GPU shapes with no cluster fabric at all, and Azure's NC H100 sizes are PCIe NVL cards rather than SXM.
For a single-GPU job or inference that difference barely matters and the cheapest row wins. For multi-node training it dominates: without a low-latency fabric the collective operations that synchronise gradients become the bottleneck, and a nominally cheaper GPU-hour can cost more per unit of work. Check the machine type, not just the price.