I like this approach. We use YNAB's budgeting software and one of the first four rules is to 'give every dollar (pound) a job'. Even if that means allocating it to savings or emergency funds.
Lychee has had little interest in money, and despite being given the same amount as her brother on a shopping trip, she will choose one small item and show no interest in budgeting and doesn't want the rest of the money.
It hasn't really bothered me, but maths wise I think she should at least be able to recognize coins.
Enter the shop.
We have built a little shop area in her room, and initially play involved paper money that the children made themselves - mostly £99 or £10000000000000 notes. Recently though we have given her a little purse with some spare coins and she has been having so much fun with it.
Playing shops today I realized she is now recognizing 20p, 5p and 1p fairly consistently. She still has no idea about 2p, 50p or a £1 coin, but we are getting somewhere.
Plus we are having fun.