Noita – Effects of Drinking Worm Blood

You can drop the tablets on the altar located
_{(spoiler alert)}

to the right of the cave entrance, on a flying island right above the mountain.

This gives you a small amount of gold (150 IIRC), but also has a small chance of

summoning strong flying monsters.

Also, the tablets can be used as improvised projectiles.

By default, Steam will sync your save games every time the game exits. You can disable this easily:

1. Right-click the game in the library and click "Properties".
2. Go to the "Updates" tab.
3. Uncheck "Enable Steam Cloud synchronization for Noita.

For some reason the cloud synchronization is really slow for this game. That is something you probably can't fix; you might want to take it up with the developers or Valve. It could have something to do with there being an unusually large amount of files within LocalLow/Nolla_Games_Noita/save00 - 451 in my case.