Stripe: It seems I always need `->createAsStripeCustomer()`?

I'm creating a SaaS and it seems that it would work better if I call createAsStripeCustomer() in User boot method right after creating (created)? Otherwise methods suchs as this fails:

auth()->user()->subscribed('main')

However the documentation says the following, and that confuses me:

Occasionally, you may wish to create a Stripe customer without beginning a subscription. You may accomplish this using the createAsStripeCustomer method

So how do you handle it for SaaS? I thought about creating a ´isValidStripeCustomer` method, but it's gonna be a lot of checks or maybe I should override the methods such assubscribed` or simply make every user a Stripe user?

And also would you create free users in Stripe under a free plan?