[thaurelia]

Comparison sites will give you ±150 Elo relative error (with I assume P=0.95).

150 Elo on levels below 2700 FIDE is almost night and day difference.

Chess.com ratings show nothing about theoretical FIDE ratings. Comparison tables have been built with data mining and lucky guesses, there's no quality difference between Chess.com <-> FIDE and LiChess <-> FIDE.

[ajkjk]

Yes they do show 'something'. They correlate with them.

It's just a fact that chess.com ratings are closer to 'real' ratings than Lichess are. It's not perfect but that doesn't mean it's a zero-information statement either.