The use of futuro perfecto other than "I will have finished"

Question

I watched a movie yesterday (translated from English to Spanish), in which one man asked another the following with the following translation to Spanish:

English original: "It has been an enormously profitable, as I imagine you noticed" = Spanish: "Esto ha producido cuantiosos beneficios, como imagino que habrá observado." [it was in both speech and subtitles and subtitles have different text in other places from Spanish speech, so this shouldn't be a mistake of translation]

Why in this scene futuro perfecto was used?

Also, in general what is the usage of futuro perfecto besides similar usage of similar tense in English (ex.: "I will have it finished by tomorrow 2 o'clock")? Even here for this "2 o'clock" example in English, more simple future tense in Spanish can be used instead, I guess (either futuro simple or present simple or voy a + inf). I rarely if ever encountered use of this tense (futuro perfecto) in Spanish.

By the way, in same scene the guy said: "Como seguramente sabrá" and in original in English it was "As you probably know". But here I know that futuro (simple) is sometimes used for wondering in Spanish. If I am wrong, please correct me.

Answer 1

If you know about the use of the future for wondering, then you have half-answered yourself. Note that the use of the future tense for wondering respects the tense in which the original sentence is written, so the transformations are as follows:

Como seguramente sabe ⇒ como seguramente sabrá
Como seguramente ha observado ⇒ como seguramente habrá observado

As sabe is in the present tense, you use the simple future. But ha observado is an action that has just happened and is in the past, so the "wondering future" applies to the haber verb, hence habrá observado.

Other similar examples:

No quiero ni imaginar cuánto dinero te habrás gastado.
La de aventuras que habrá vivido ese marinero.
—Hacía tiempo que Fulano no venía por la oficina, ¿no? —Habrá estado enfermo.
¿Habrase visto semejante desfachatez?

You can read more about the futuro de conjetura applied to this tense in paragraph 23.16r of the Spanish Gramática, where you can also find an example in the first person singular:

Pedí una semana de vacaciones y aquí estoy. Algo habré venido a buscar.