...In my perspective, it does not a problem to wait for 5 or ten minutes to get finished transactions between exchanges/ platforms and I see there are so many coins satisfy that need of crypto enthusiasts nowadays...
I can't agree with you here and I am sure that many will choose the coin which has instant or even lightning-fast transactions rather than slower once.
This is very important for many treaders, especially when you are trading using bots or API. Still, LTC is a lot better as BTC for which I waited yesterday almost 7 hours to be confirmed.
As I already said I have used LTC in 2018 very much because was one of the best options for fast and cheap transfers, today I amusing other alts so situation changed and LTC lost this advantage already because there are a few cheaper and faster coins only in the top 10, don't mention other once.
That is why further development of new features as Mimbewimble is a great idea and will add value and more use cases for LTC.