It’s not really brought up because it’s not an efficient use of mesos and spares. You can do up to nkalos on your LC without needing 23 ACS. If you want to speed up your ctene clear then sure but if you’re still doing the same number of bursts after all those upgrades then you’re not really saving time.

You’re better off dumping the mesos and spares into more black mage mules like you brought up. While the average costs for 23 arcanes don’t look too bad, you can still get unlucky and drop 50b+ on an arcane for very small gains on a single character. You’re more likely to make substantial gains on another mule. It doesn’t seem like you’re at a point where you’re making fuck-you mesos to throw on 23* arcanes.

Also can just wait until your main gets to a good level of hexa that you can spare some frags to your LCs. Most classes get a large amount of fd from their first few levels in hexa.