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The SFT25R has less output and more throw because it has a smaller (and round) light emitting surface. It is usually used for applications where maximizing beam distance in a given optic size is the primary consideration.
3000K looks similar to a halogen incandescent - slightly less yellow than a traditional incandescent. With these specific LEDs, there's another consideration: the 3000K option has a very high color rendering index, while the others have low CRI. While CRI is independent of color temperature, the SFT40 that Convoy stocks pairs 3000K with 95+ CRI, meaning that colors, especially red/brown/orange colors will look much more vivid and accurate with that LED. The Nichia 519A LED is also offered, and it has high CRI at every color temperature except 1800K.
CRI costs efficiency, and it's especially costly with the SFT40. The high-CRI version has less output than the low-CRI version. Human perception of brightness is roughly logarithmic such that moderate differences are hard to notice, but it is enough to notice in that particular case.
as I understand, lights with built-in charging functions (e.g. Skilhunt EC150) usually don’t work with NiMH batteries, only Li-ion 14500 batteries
This is not correct. The Skilhunt EC150, M150, and H150 can be used with NiMH batteries, but they cannot charge NiMH batteries internally. There are some lights that only work with 14500 batteries, but that's determined by their driver electronics, not whether they have onboard charging. The Wurkkos TS10 and dual-channel versions of the Emisar D2 are examples of lights that require the higher voltage of a Li-ion battery.