The question is not what is the strategy to set Win Chance as player, but what is the strategy for the casino house to define Win Chance limits.
I think you should probably read their terms if there's any about the win chance limits but I guess that's for confidentiality on casino's end, correct me if I'm wrong. I guess it's more of a tradition and on some notable dice sites I played mostly it is always 0.01 to 99.98% win chance limits.
None of the casinos that I checked (about 10) declared any terms where Win Chance limit logic is defined.
Doesn't look like this is some secret topic. It boils down to allowing very small payouts. I think the worst case is that for example:
HE = 1%
Win Chance = 99.00%
then multiplier will be 1. It means if player bets 1000€ and lucky, then he will just get his 1000€ back. Only risk here I see is accumulating wager for cheap price if casino is running anything on wager.
Allowing more than 99.00% doesn't make sense, because then it becomes unlucky bet automatically.
But what is wrong with range 98-99%? Why casinos are avoiding this range?