Perhaps surprisingly, round-trip efficiency matters a lot less than other things, for storage not drawn down often. And, it matters a lot less everywhere than only a short time ago, because top-line generating capacity has got so cheap, you can just build out enough more of that to make up the difference. If your liquified hydrogen is slowly boiling away, you just top up your tanks now and again.
The important difference from batteries I call attention to is that in batteries, you can only store exactly as much energy as you buy expensive batteries to keep it in. But for synthetic chemicals (and liquified nitrogen), the only expensive parts are what you use to synthesize them in, and maybe the way you get the energy back. Those capacities are measured in watts. Saying tankage is cheap is to note that there is no upper limit on the amount of tankage you can have, and the watt-hours you can bank; your bottleneck is only the conversion rate.
This is all aside from the fact that tankage can be shipped, both out, generating revenue from excess generating capacity, and in, if local storage gets drawn down too far.
So, batteries will be used for short-term storage. Iron-air battery factories are under construction, and those will be much cheaper than lithium, and will be used, but however much cheaper they are than other batteries, they cannot match empty tankage.
