Are there any advantages in using SMTP

Using a custom SMTP service to send out emails from Quickmail has its advantages and consequences. Here are some of them:

Pros:
1. Sending could be less risky from a SMTP provider like SendGrid, MailGun, postmark ...
2. You have one added level of backup for your client. e.g. your primary inbox provider like G Suite or Outlook won't block you since you use something else to send emails, and therefore your client can keep using emails normally despite your cold email activities.
3. You can handle bounces at the provider level so your clients won't see them in their inbox
4. Volume sending can be less problematic than with normal G Suite
Cons:
1. Cold email is generally against their policy, so you risk being terminated without much consideration (same for G Suite blocking you)
2. Because bounces are not landing in inboxes, QuickMail won't see them and will send follow-ups to those who bounced already.
3. Need to perform some tests to see open tracking/click tracking and unsubscribe works properly. Sometimes the tracking interfere with the one of QiuckMail (but that's usually a bad configuration problem and easily resolvable)
4. Deliverability can vary drastically and you stand more chances of ending up in the promotional tab unless you setup white-labelling (highly
recommended, but requires some changes of DNS, which may be tricky with some clients). Most service will use shared IP, if you want your own one (which can be a real advantage for monitoring complains and handling reputation), it costs additional charge.