I have used CSS Grid for my very first and only live website (not for a client), I tried many responsive methods and techniques and in my experience none could be easily implemented as CSS Grid, add on that I had written much less code with it (compared to other methods) to achieve the final result.
I love it, despite the fact that not every browser supports it. For example, UC Browser, Opera Mini and IE. But I am taking the risk as eventually it will have wider support in the future.
In Google Analytics I have seen a lot of 100% Bounce Rate, with further investigation I found out that a whole bunch of them are due to the fact that those users browse using non-supported browsers. As the website looks broken (not showing Grid) so eventually they quit from the first glance.
I guess you have to evaluate your own situation and decide upon that.