Some of the omitted symbols here were thought to have already appeared earlier in Unicode

For example U+2110 is "Script Capital I" and looks like ℐ allowing U+1D4A4 to be ignored

while U+210E is "Planck Constant" and looks like ℎ allowing U+1D455 to be ignored

Try the Letterlike Symbols block to see more examples

Some of the omitted symbols here were thought to have already appeared earlier in Unicode. Your Wikipedia table says in a note

The reserved code points (the "holes") in the alphabetic ranges up to U+1D551 duplicate characters in the Letterlike Symbols block

For example U+2110 is "Script Capital I" and looks like ℐ allowing U+1D4A4 to be ignored

while U+210E is "Planck Constant" and looks like ℎ allowing U+1D455 to be ignored