How much VRAM are we talking about here... and what resolution/settings etc?

Tbh though it's probably nothing to be concerned about. Much like RAM, if the resources are there the game will allocate and/or use them. Same way you want your GPU to be running very high usage to get the most out of it.
As for the unlimited VRAM usage checkbox, my understanding is that just enables the game to start queueing up RAM to use to fill in for any lack of VRAM and can be counter to the desired result. Leaving it off won't cut or reduce VRAM use. Assuming you have at least 4Gb VRAM at low 1080p (and upwards from there) I'd leave it unticked.

My GPU has 6gb VRAM. Game is at 1080p and I've limited it in NVIDIA settings to 45fps. The in-game graphics were set to various presets from the dropdown, but none made any difference - from ultra to low, with game restarts in-between, all consumed 6gb of vram.
It is a concern, as I have recording software that requires a small amount of vram, and with the game hogging it all the software begins to lag. This shows up as fps drops in the recording even though my game's fps is smooth.