Question about new validation rule for "no spaces in tenant's name" #12691

We are upgrading to 15.3 and it seems like there is now a new validation rule to prevent the user from using spaces in a tenant's Name. This validation rule was previously only there for the unique TenancyName, but spaces were allowed in the Name property (or at least we have been doing it this way for years).

Why is there a validation rule to prevent spaces in the tenant's Name field? We have a lot of lecacy tenants with space in their names and were planning on removing this validation rule, but I wanted to see:

1. Why this validation rule was put there in the first place (what problem is it designed to solve)
2. Are there any possible unintended consequences if we allow spaces in the tenant's Name (but not, of course, in the TenancyName)

Thanks in advance for your reply and explanation.

-Eric