Your body does not create B12 - you need to get it from animal products, dirt or supplements. It is water soluble and large amounts are not harmful. Too little and you could be in trouble.
People say vegans can suffer from B12 deficiency and this is true, but so can many people, especially as you get older. Symptoms of deficiency are not good. Energy levels can be low, you can get nerve damage, be susceptible to strokes and heart disease.
As a long term vegan it is the one vitamin I have supplemented. I use tablets and a sublingual spray. I use both cyano- and methyl-cobalamin. Huel uses cyano- as methyl- is not stable in food products over time.
There is no long term contraindication for B12 use, so yeah take some.