In the current version, yes – opening the Flows section at all (/admin/marketingcampaigns/flows) still checks that your sending domain's Validate Link onboarding step is complete, and redirects any non-super-admin to Onboarding if it is not, regardless of whether the flow you plan to build only uses SMS blocks. It also still requires a marketing-campaigns plan to be selected on the Billing page. So even an SMS-only welcome flow currently needs the email sender-domain onboarding and a plan (the Free plan is enough) finished first, before you can add the SMS block described elsewhere. If you only ever plan to text customers and never email them, talk to Sprwt support about whether this still applies to your account.