That is putting aside ground stations located in areas which themselves have poor transit which is the main problem with regional variability of performance I would imagine, though could also be congestion if they are oversubscribing in those regions. i.e too much density of terminals.
Starlink will make those who would benefit (hedge funds, mainly) pay through the nose to get it. And, pay even more to keep somebody else from getting it. Probably they will charge a huge premium for 1ms faster than fiber, and 100x more for each ms better than that.
You may be certain they will not use that extra income to provide you better value.
Sending early is of course always OK. Those paying for that millisecond need it reliably every time, so not much of your traffic would need to be stalled. Maybe 10%. And maybe only while markets are open.