Ranger's Trailblazer is Useless

I can have more health and mana for ganks.

I never have to worry about smiting a champion, so I almost always enjoy a smite-benefit from a camp. Also, it's always up for dragon/baron.

1. I don't have to buy pots
2. I clear faster than the other jungler
3. Waveclear (especially baron minions)
4. It can save your life with HP steal

Trailblazer is probably the best jungle item so you most likely are bad at jungling.

Some jungler need it to make their transition into ganking easier as it gives them health and mana.

It actually is really good on junglers with little or no sustain, so basically "non-meta" junglers. it is pretty helpful for a quick hp/mana boost when running away thru the jungle. I have saved myself so many times because someone shot that final ability to kill me but I smite scuttle crab and regained enough hp to live and get away.

Certain junglers don't really have a strong sustain in fighting camps before ganking a lane

I buy trailblazer first and then switch to chilling smite later usually.