I mean, usually you use it only around 2-3 times a game when, usually, if you play smart, you could just use something else in the champion's kit. Also, with the champions as of late, how often does Flash by itself actually save you? Why aren't Summoners like 
used more outside of like one specific role?
Jo0o5 votesUsed well, it's versatile and very, very strong. Flash into melee range to finish somebody off, juke a crucial skill shot, get out of a wombo-combo, hop over a wall to evade pursuit or to pursue, etc. Many summoners are AS strong as flash(or possibly stronger) in a given situation, but usually, none are as strong as flash in ALL of those situations.
Mecha MaIphite2 votesFlash saved me a lot of times.
You can't barrier a Malphite knockup or ghost over a Nami wave.
Besides, it serves as a deterrent for the enemy jungler.
BeatzBoyFTW1 votesPlayed Tahm Kench support. My Adc Ashe doesnt have Heal/Flash. She got caught out. I used my W and then Flash over a thick wall to safety. Received 9 honors for it.
#FeelsGoodMan
Gary B Enkelis1 votes
is good for covering a distance quickly, for offense or defense. Also you can probably over stuff like 
ult and of course 
ult. Also going over normal walls.
I think is better for "sustained movement" like chasing with 
when he spins.
