For some - like me - it is certainly a net benefit since there is no real transaction other than me buying the hardware and paying ~€2/month for mobile data/cell service:

- the device is 'Google-free'

- I only use free software

- the thing is firewalled for in- and outgoing traffic, only those applications I approve get to access the net

- I use a 'prepaid' data card, 250 GB valid for 2 years for ~€50 (~€2/month) which I won't use up. Last time I could take along unused data to the next 2 years so nothing is lost.

Here's the 'costs':

- between €120 and €170 for the hardware which tends to last around 8 years, i.e. between €15 and ~€21 per year

- sometimes something breaks (battery, screen, speaker, USB connection board) which I then repair, can be anything between €1 and €40 so let's put the repair costs at €24 per device or €3 per year

- €2/month for data and cell service valid in the whole EU (no roaming costs)

- electricity, comes from the sun -> free

- when the device is on I can be tracked by interested TLAs like any other 4/5G device

- same is true for Bluetooth, not so much for WiFi which is normally off and changes MAC address for every connection.