But you only care about the difficulty of extracting eight-bit bytes from words because you need to do things like interoperate with protocols or storage media based on eight bit bytes, or eight bit parallel interfaces.
If everything were based on a different basic ‘byte’ size that objection would go away.
Sure, oddball things that used 8-bit data would exist and you’d need to work with them - but in our 8-bit world oddball things based on 10-bit protocols exist and we live with the impedance mismatches that causes.
6 bits isn't enough. 7 bits is viable for characters but at that point there's strong pressure to move up to 8 as a power of two. 9 fits neatly into octal but there's little advantage over 8 so you're probably going to prefer either 8 or 10.
Between 8 and 10, I could see 10 winning. But either way octal isn't doing very hot.
If everything were based on a different basic ‘byte’ size that objection would go away.
Sure, oddball things that used 8-bit data would exist and you’d need to work with them - but in our 8-bit world oddball things based on 10-bit protocols exist and we live with the impedance mismatches that causes.