That's certainly a unique way of converting coin flips to a seed phrase, but I really don't like the way it is laid out. Once you get down to the green/blue/purple lines, it becomes far too easy to make a mistake. If you are following the table in real time as you work along 11 flips, it also becomes easy to forget your place.

Further, if you are going to create the full seed yourself, then you need to calculate the checksum yourself, so you still need the 128 or 256 bits in binary to plug in to a SHA256 function. My method has always been to simply write down 0 for heads and 1 for tails (or vice versa), convert each 11 bits to decimal, and then map to the word list direct from GitHub (https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt). You don't risk the mistake of losing your place, you have everything written down so you can double check it, and you can easily use the number to calculate the checksum.