One dotted quarter note,
one eighth note

One beat and ½,
½ beat

One quarter note tied to
two eighth notes

One beat and ½,
½ beat

One quarter note,
one eight note rest,
one eighth note

One beat,
½ beat,
½ beat

As you can notice, there is no difference between the first two ways of writing this rhythm.
The results are identical and no mistake is made by writing in one manner or the other.
The third way of writing, on the other hand, shortens the first note.
Yet, in many circumstances, you would hear little difference, mostly if the tempo is very fast.
The fact the same rhythm can be written in different manners makes reading them back harder.
It is best to get used to reading them all, even if some seem easier

A: Start by doing this rhythm, using the syllable "Ta".

B: Remove the "T" from the second "Ta".

C: Hold the first "Ta".