Of course I know he can it forever but from what I've seen, it hardly takes any chakra. Feel free to show me where Minato bgins to show the slightest fatigue from FTG.
Show me where Minato has used FTG for the entire duration of a battle and I'll gladly show you where the manga indicates that it takes chakra to use. Because right now that's you Minato fanboy's main go-to argument.
But you sasuke fans on the other hand seem to think that EMS takes less toll on Sasuke than what FTG does on Minato. The only reason Sasuke has spammed in the past is because of Karin restoring his chakra all the time. The time Sasuke ran out of chakra against Deidara and should have dies, PNJ gave him chakra to summon freakin manda. But realistically no Sasuke cannot spam EMS longer that Minato can spam FTG. The toll Susanoo and Amaterasu is much more severe.
No one's saying EMS takes less of a toll on Sasuke than what FTG does to Minato. Minato simply does not have an unlimited amount of FTG. Every jutsu has a weakness, and unfortunately that appears to be FTG's weakness: limitation.
Also Sasuke never really spammed when he had MS. Because it induced fatigue on him. EMS can however be spammed which has been shown recently in the manga. He used EMS over 3-4 times in one day. No signs whatsoever of tire. Karin healing him is an irrelevant argument.
Furthermore, Sasuke defeated Deidara. Sasuke pushed Deidara to exertion and forced Deidara to commit suicide due to being at a stalemate. Sasuke also said he was holding back in that battle and didn't have the intention to kill him. Also how Sasuke escaped was a form of space time ninjutsu. No he didn't solely summon Manda to escape. You're implying that battle wasn't a legitimate win by Sasuke despite it being 2v1 (Tobi/Deidara) and Sasuke still won.