Is cold email still a thing to promote apps?

Cold emails are absolutely still a thing. But you have to be intentional about how you use that tool. Also, cold emailing may not be a sustainable/scalable channel in later stages when you already got your first users. Easy way to tell if you should be doing cold emails: try to do a bunch of them, genuinely writing personal emails to people you think will absolutely love your app. If it works — continue. Do so as long as it works but not less than a month (consistently).

It may not work as expected all the time, but you have to consider it as a marketing option initially. Nothing is entirely foolproof, including cold emailing.

Is cold email still a thing to promote apps? Hell NO. I have done so much cold emails and from all the emails send, Nothing new even a reply. Once I move to private slack server I get 90% chance to get a reply.

Cold emails work if done properly! Although "cold", they should be relevant, personalized (most importantly), and honest. "Copy-paste" cold emails rarely worked for me!

Cold emails still work.

YES, cold email is a thing, there is a process to it that you need to go through to make it work, scalable, of course, everyone on the internet has an email.

Everything on the internet is cold, this is exactly the reason why there aren't any "hot" emails. Instead, there is 'Hotmail', which is again used for cold emailing.

And look at which platform you are promoting your app, LinkedIN is great for connecting with people where as Instagram is good for showing your product visually.