There are definite benefits to setting a Signing Order, such as where a hierarchy of approval is required, Department to Vice President to President. I have found one of the downsides of no Signing Order is the inability to tell where the envelope is stuck in the envelope process and if using “Resend” then everyone in that parallel order gets a new notification who has not taken action.
Also Signing Order can be quite flexible in that you can set several parallel orders so that two Recipients are set as “1” in the Signing Order, and another 5 Recipients can be set as “2”, making the Signing Order into groups. There are upsides and downsides of course and use what works best for the outcome of the envelope.