SAFEs are much faster, cheaper, and easier to execute. You don't need lawyers when it comes to negotiating terms, no board setup, etc. It is helpful if you are raising and don't have the full round committed upfront (which is the typical situation for Alchemist startups).
SAFEs are also more founder-friendly because you will retain more control (no board, fewer investor rights). SAFEs are pretty standard for Pre-Seed/Seed rounds. Most angels & early-stage funds are used to the, especially for <$2M rounds. Priced rounds usually make sense if you're raising ~ $2M+ and if a lead VC is coming in / wants ownership clarify.