Since mtdna is only inherited through the mother,does that mean we are
all more related to our mothers than our fathers?Also does that mean
half siblings with the same mother are more related than half siblings
with the same father?

Technically, yes, but mitochondrial DNA contains very few genes
compared to the human nuclear genome, at a guess, it is about 0.1% of
the size.

As well, genetic information in mtDNA does not have any substantial
impact on the phenotypes expressed by the rest of the human genome.
For all intents and purposes, mtDNA is ignored when considering traits
like hair colour or eye colour. mtDNA may have subtle impacts on
energy synthesis, as mitochondria are involved in cellular
respiration.

mtDNA is most useful for tracing family lineages, as it does not
change as it is passed from generation to generation (notwithstanding
mutation or replication errors).