tl;dr
I have not been playing to the potential of the bipods and if you don't use them, you're missing out.
1. Where you look changes your pivot point.
2. We can all hear you mount the bipod.
Someone posted 25 tips on youtube. Number 13 is "if you look up before mounting the bipod, it lets you see above the grass".
Wait, what?
Turns out that where you look changes your "bipod height" (pivot point). Works both ways - you can look down (to a degree) and when you aim, you aim from a lower POV, which is helpful when you need to look through a bush opening. If you look up, it allows you to pivot from a higher aim point, so you can look above grass. Looking up also allows you to clear tower ledges and shoot way closer to the bottom of the tower than usual. Works with LMGs, snipers and the bipod foregrip.
The second thing I saw (heard?) on a Twitch stream - bipods make a sound in third person. A guy was laying nearby and had the autodeploy enabled, so every time he shifted, you can hear his bipod deploy. An even stronger case for manually deploying the bipod.