We're helping to support conversational customer support agents that can help users better during off-hours and scheduling assistants that can interact with and understand user requests better than current models over SMS/RCS. This is definitely not just spam but instead the future of conversational 2-way messaging.

I don't think anyone would be expressing the same level of concern if the conversations were only started/triggered by an inbound [to you] message.

Commingling things like cart abandonment and (actual, user-initiated) conversational messaging dramatically increases the risk that Apple takes action, from my point of view.

Yes, I agree, which is why we try to make the opt-in clear. Use cases like form-fill text back or cart abandonment after the user has opted in and noted down their number are what we primarily focus on

No one ever “opts in” to nagging cart reminders just because they were forced to fill out a phone number to estimate shipping

I don't know why you're so insistent on trying to build a business on quicksand. Please just stop before you waste any more time or money on this.

They just got 500k from YC, I doubt they'd pivot until they get big enough for Apple to notice, by which point they might cash out.

YC will throw money at anyone I guess

YC also funded Sendblue which does something similar: https://www.ycombinator.com/companies/sendblue

It looks like a straightforward ToS violation to me as well. I guess it's another "ask forgiveness, not permission" move.