This is almost exactly the same as coda.io, which is much more polished, and I highly recommend for small data. Just looking at grist for the first time now it seems like it might not have commenting, which I find very useful sometimes for collaboration. Grist though is open source and seems to have an embeddable version.
formulas are a big part of coda and so much easier and safer than excel. I don’t know what layouts and access rules are in grist, but there are similar sounding features in Coda as well.