It's impossible to actually anonymize telemetry data, they can only promise they don't tie the data to your IP, FF account, or any other data their servers can'

It's impossible to actually anonymize telemetry data, they can only promise they don't tie the data to your IP, FF account, or any other data their servers can't help but know specifically about you. A quick search will reveal plenty of historic examples of breaking promises just like that one, with very little repercussion.