Hello webqa test,
It might help if you could elaborate on ROI vs something else e.g. ROI vs ESXi+SAN or ROI vs Physical Servers+SAN.
While there is the added cost of vSAN licensing when compared to a traditional ESXi+SAN set-up, the cost of the commodity hardware required to run vSAN well is relatively little compared to the cost of even an entry-level SAN+any additional required networking modules for this.
vSAN can be a really good solution for small-medium sized companies or remote offices that would get very little SAN for comparable price of a vSAN cluster - this isn't to say that vSAN can't go big either, I am seeing a growing number of 20+ node clusters in use for production environments.
vSAN also has easily-configured redundancy via SPBM that could save a lot of money when compared to other additional FT/DR/replication technologies that might need to be used (and payed for) otherwise.
Bob