Some companies now require you to have an account. I’ve not really travelled with anyone but TPE or Northern since the first lockdown on March 2020 but TPE definitely force you to have an account now.
Registering an online account isn't difficult or time consuming really, and if you don't use that company regularly, once you've made your one claim, you can forget you have that account.
Similarly, the few times I've done it I haven't found delay repay claims to be too difficult to complete. The information asked for is all relevant, and the online form works.