Warlock Eldritch master good for nothing?

I find the Warlock level 20 feature Eldritch Master totally useless as it states:

Eldritch Master: At 20th level, you can draw on your inner reserve of mystical power while entreating your patron to regain expended spell slots. You can spend 1 minute entreating your patron for aid to regain all your expended spell slots from your Pact Magic feature. Once you regain spell slots with this feature, you must finish a long rest before you can do so again.

But your spell slots are always recharged on a short rest.

Spell Slots: The Warlock table shows how many spell slots you have. The table also shows what the level of those slots is; all of your spell slots are the same level. To cast one of your warlock spells of 1st level or higher, you must expend a spell slot. You regain all expended spell slots when you finish a short or long rest.

So, what’s the point of Eldritch Master? I thought that maybe an errata and the recharged slots are the ones from Mystic Arcanum, that would be a good 20th level feature.

We are using a short rest variant that makes short rests 5-10 minutes instead of an hour.