They are different places, not competitors
Email is where newsletters, receipts and attachments live. A text arrives in the same list as messages from the customer’s family. That difference in setting is the whole argument, and it cuts both ways: a text is harder to ignore and easier to resent.
When a text is the right call
Anything that loses its value by tomorrow. Reminders, on-the-way notices, ready-for-pickup alerts, a same-day offer, an urgent reschedule. If the customer needs it in the next few hours, put it in a text.
Keep it short and make one request. A text is not the place for terms, disclaimers or a price list.
When email is the right call
Long form. Quotes with attachments, itemised invoices, newsletters, anything the customer will want to search for in six months. Email is also the correct home for anything that is not urgent, because sending a non-urgent text trains people to ignore the urgent ones.
The pattern that uses both
Email the detailed quote, then text: “your quote is ready, check your inbox.” The email carries the detail and the text does one job, which is making sure the email is opened today.
One thing a text does that email does not
The message comes from a real Australian mobile, so the customer can reply to it like any other text. That reply lands on the sending phone. It does not appear in the AussieSMS dashboard, which is worth deciding about before you invite two hundred people to answer.