The 100 satoshis spend on inviting can be like an investment for the person who invites.

And from all the tips and total generated by the person who is invited gets in his account the inviter gets a share of that. say like 10% or so

That will incentivise some people to become active inviters putting in 100 satoshis to invite and take the risk and get the reward of perpetual income stream coming from the invited accounts.

If someone invites he can be given a dashboard to help him see how much he spend on each invites and how much is the rewards coming in from each person invited.