Yes. Counters only support integers (whole numbers, no decimals).
You could use an input_number instead.
input_number:
pocket_money:
name: "Pocket Money"
min: 0
max: 1000
step: 0.01 # chage this if you want to step in dollars or quarters or whatever
unit_of_measurement: '$'
icon: mdi:piggy-bank-outline