I don’t use glimble for personal travel. Do I still need to link a payment method to the app?

No. In that case, it is not necessary. You can simply link glimble to your glimble in business account and just use it for business travel. However, please note that to use shared transport, you will need to link a personal payment method to your account. Then if the cost of shared transport exceeds your business travel allowance, the difference can be charged to your payment method.