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 for yesterday almost 7 hours to be confirmed.
There are different types of crypto traders, and investors and they have different needs to move their coins (speeds, fees, and potential congestion on networks). Someone don't have urgent needs like me, someone have urgent needs or just usually need fast transactions like you.
Addtionally, their definitions on fast transactions are different, obviously.
Generally, the diversification of demands from crypto traders and investors result in a very healthy competition and race between different crypto currencies. It's good for all.
That is why further development of new features as Mimbewimble is a great idea and will add value and more use cases for LTC.
This is what I totally agree with you. By the way, it is good to see you point it out when Mimblewimble-algorithm coins have been in their upwards trend, from Grin coin to BEAM.