Are These Cinderellas?

I'm not sure if this is in the correct forum, but I just returned from a cruise where I made a point to pick up stamps from each country. In an Azores tourist shop I got several stamps from tugapost and in a similar shop in Spain got one that says "Post by Me". I know that if these stamps are used and put in a special post box they go into either the official Portuguese or Spanish mail system and are deliverable.

From a collectors standpoint are these legitimate collectible stamps. I realize that this is a dumb question in that it is my collection and I can collect whatever I want, but do these rank among collectors akin to the Eastern European or Middle east precancelled stamps that some collectors see as junk?

All other stamps I got were from Post offices so have no question about them.

It would be a better question if you'd post a picture ? The tea leaves aren"t working today !


Peter

"Post by me" and "tugapost" are private post offices.
Private post offices exist in many European countries including Germany and the Netherlands.
Their stamps are quite legitimate in my opinion.

There are collectors of these stamps. Album publishers, however, will not include them.

They, mostly, operate in tourist towns. You may find that the stamps are available from outlets in the centre of Barcelona, but not on the outskirts where tourists rarely come if not sitting on a bus to pass through as quickly as possible. Collectors might struggle to find them. So, it will not be profitable for album publishers to publish albums for them.

tugapost is a legal Portuguese private postal service, licenced by Portugal authorities. They have their own mailboxes for postcards.
post by.me is a legal Spanish private postal service operating in tourist places. They also have their own mailboxes for postcards.
(I have no idea what happens if you drop your postcards into "normal" mailboxes)

If deposited in a Correos postbox, the post will be collected and, periodically, transferred to post by.me, causing delays, but not loss of the post.

If deposited in a postbox of another company, it will be a lottery.

See the company's Q&A page: