> What do you mean by frictionless payments?

I mean in the same way as email is frictionless compared to mail: you can send all day, it arrives halfway around the globe in seconds, fees are significantly lower.

> What services in particular?

For most people? Money transfer.

> And what's preferable about using blockchain technology for these services?

AFAIK because it is a way to make this happen without having to trust a number of institutions that are rich because of the current setup and might have a huge conflict of interest.

Again: IMO this is about the technology, not about Bitcoin.