SMS and email are both legitimate B2B channels, and the "which is better" debate misses the point. They're good at different jobs. The mistake businesses make isn't choosing the wrong channel overall — it's using the wrong one for a given moment, which is how a useful message gets ignored, or worse, resented. Here's how the two actually compare and when each fits.
What email is good for
Email is the workhorse for substance and patience. It handles longer content, documents, detail, and anything the recipient might want to keep or reference. It's expected and non-intrusive — people process email on their own schedule, so it's right for things that aren't urgent: the quote with details attached, the newsletter, the follow-up that can wait until they're at their desk. Email's strength is depth and the recipient's control over when they engage.
What SMS is good for
SMS is the channel of immediacy. Texts get read fast — far faster than email — which makes them right for the urgent and the time-sensitive: the appointment reminder, the "your order shipped," the quick confirmation. But that immediacy is exactly why SMS is intrusive: it lands where people get messages from friends and family. Used for the wrong things, or too often, it feels like an invasion, and the goodwill burns fast.
The rule of thumb
Match the channel to the moment. If it's substantive, can wait, or needs to be referenced later — email. If it's urgent, brief, and genuinely time-sensitive — SMS, sparingly. The error is using SMS for what should be email (intrusive) or email for what should be SMS (missed because it wasn't urgent enough to compete with the inbox). And SMS carries real compliance obligations email doesn't — consent and easy opt-out are non-negotiable, since the rules around texting are strict and vary by jurisdiction.
Don't pick a channel and force everything through it. Use email for substance and patience, SMS for genuine urgency and sparingly — and respect that SMS's power to get read instantly is also its power to annoy. Matched to the moment, both channels work; mismatched, even a good message lands wrong.