Thai amulets (some Burmese, some Cambodian) are mostly thought to be of Buddhism.
This statement is only half correct.
Taking an excerpt from http://www.accesstoinsight.org/lib/authors/ariyesako/layguide.html#nonos :
Bhikkhus are also prohibited from studying or speaking on 'low animal-like knowledge' (tiracchaana-vijjaa)
"The explanation of [low animal-like knowledge] seems to cover all general subjects which are not related to the Dhamma of bhikkhus. [These are:] knowledge of enchantments making men and women love each other; knowledge for making this or that person fall into disaster; knowledge for using spirits or showing various kinds of magic; knowledge of prediction, such as knowing beforehand lottery results; knowledge leading to self-delusion, such as transmuting mercury to gain the supernatural, as in the transmuting of silver and copper into gold.
"These knowledges are ['low animal-like knowledge'] because they are knowledge of doubtful things which are deceptive or deluding, not being true knowledge. A teacher of this is a deceiver and a pupil is one who practices to deceive, or he is just a foolish, deluded person." (EV,II,pp.120-121)
This is something clearly forbidden by Buddha himself, stated in Vinaya Pitaka.
However, Vinaya mention nothing about protection, healing of ailment or improving one's life.
So does this prohibition applies to Thai amulet ?
Again, yes and no.
For example, amulets with Maha Saneh effect are produced massively.
Does a real Buddhist need this type of amulet ?
Is up to you, owners or colelctors of amulets to judge.
If you are trying to follow real Buddhism (and wear Thai amulet), consult a proper Buddhist monk.