that's not foolproof though. in fact, it's kind of worthless. just because you have 3 or 4 of the words correct doesn't mean you have all of them. i think it give people a false sense of security. plus lets be honest most people probably skip over that step if it's not required.  


if it was that simple people wouldn't come on to this forum saying their seed phrase isnt "working". maybe they should use a computer printer to print it out that way they are guaranteed to not make any transcription mistakes. the probability of making a transcription error is much greater than any security risk that might occur by using a computer printer at home.

well here is what they said:


This implements a BCH code that guarantees detection of any error affecting at most 4 characters and has less than a 1 in 109 chance of failing to detect more errors.

that is the part that sounds good. the part that sounds bad is the following:


Error correction

One of the properties of these BCH codes is that they can be used for error correction. An unfortunate side effect of error correction is that it erodes error detection: correction changes invalid inputs into valid inputs, but if more than a few errors were made then the valid input may not be the correct input. Use of an incorrect but valid input can cause funds to be lost irrecoverably. Because of this, implementations SHOULD NOT implement correction beyond potentially suggesting to the user where in the string an error might be found, without suggesting the correction to make.

being able to detect up to 4 characters that are in error sounds good but if it can't fix it too then i'm not sure how useful it is. might as well just use a simpler checksum mechanism. one that can't fix anything just detect.