I like this idea a lot, personally. Separately deployed customer instances as an approach for “multi-tenancy” also eliminates the need for sharding databases at scale, since most of your scaling will just be new deployments. Overall, this suggestion has an appealing set of trade offs if you have the DevOps chops to pull it off.
Just watch out for really really big customer instances (but then they should be paying more than enough to spend time on their particular scaling issues).
I realized after commenting if it is specifically a product where you actually need / want these customers' data to "talk" to eachother, then actually your architecture might be a bit simpler - then you can expose what you need between all the tenants. I can't speak to this approach much more though, since I haven't done a project like that yet.
Just watch out for really really big customer instances (but then they should be paying more than enough to spend time on their particular scaling issues).