A few weeks ago I bought from a new-to-me store.
Within that same week they emailed me three times about other products they have and a kickstarter they were starting. 100% sales messages.
Basically, I got dumped into their main newsletter without any preamble and right in the middle of a conversation (their kickstarter).
While I 100% believe new customers should get on your main newsletter eventually, they need to go through your new customer welcome campaign first. You need to welcome them, give them some information about their first order or your company, and then transition them into your main newsletter.
Dropping them right in is disorienting, confusing, and it more likely to have them think their email was sold to a spammer. Not the experience you want for a new customer.
The welcome campaign doesn't have to be long or complex either. My own is only one email.
Done right, the campaign will get new customers into the mindset of becoming a repeat customer.
Optimize your promotion timing to save money and attention
Repeat Customer Insights will analyze a ton of customer behavior data for you, including their buying cycles.
If you knew exactly when the majority of your customers were ready to buy again, you can increase your orders and profit just by tweaking your message timing.