Unlike what? Android? iOS?

I dare you to close your eyes and install a random free app on the Play Store or Apple App Store. Chances are high you'll download some malware.

Pinephone just runs Linux distros, which have a good track record.

My Linux environments are open -- I am free to obtain and run software from wherever and whomever I please, and they're not infested with malware. I apply my own reasoning and decision-making, which includes considering the reputation of the source(s). It has worked out fine for many years now.

We can have openness and still be thinking of the children. /s

What's it to you? We did this exact thing with Windows for nearly 20 years and the world didn't end.