Some circuit boards are given a “conformal coat” (like a varnish coat) to prevent short circuits from the growth of “tin whiskers”.
Sounds like the old Ma Bell model of renting your telephone. And since they were on the hook (pun intended) for repairs, they made their telephones rock-solid sturdy.
Washing machine parts are given a conformal coat (or potted) to prevent corrosion by wet spray containing dissolved oxidizers.
There was a time when bright-tin-coating was common, and then there was a later time when people considered returning to bright-tin-coating. Although the linked document was last updated 2019, it actually dates from the previous decade when American suppliers were moving to alternatives to tin/lead solder. EU ROHS came into effect in 2006.