Safe is probably favored to become the standard vehicle for seed rounds, a benefit of being sponsored by YC. Investors will require less convincing and at first glance Safe seems to be at least as good as convertible debt (as fast and cheap as convertible debt, with no promise of repayment).
That's certainly valid from a marketing standpoint. Although, convertible equity was published WSGR, which may not be a household name, is still an entity that anyone in the funding game should be familiar with.
I'm really more interested in whether there are significant structural differences between the two schemes.
