Hiya.
As far as my own opinion on tier lists, here's what I think:
If you're in the competitive smash scene, then tier lists can be a great help determining who the best and worst characters are (and everything in-between) so you can know which characters to watch out for and how the meta in general is developing.
If you are a casual Smash player, then you don't need to worry about tier lists because tier lists are for the competitive scene rather than the casual scene.
Their value is ultimately very dependent on the person. If you are a competitive Smash player, they most certainly matter. If you are a casual player, they barely matter at all.
Those are my thoughts. I hope it helped