Hi, guys ! I do lots of translation Spanish to English & vice-versa, I also used to teach Spanish, being my 1st language, but some terms and concepts just don't translate well into Spanish, let's see if I can explain better what IMO these 2 terms are
1) Bienes y Raices (literally meaning "ASSETS AND ROOTS") was the original term I believe long ago for the "real estate" concept as we know it in the US, it is a weird term even for a hispanophone "bienes" as well as "raices" are both nouns here. Afterwards the coined term became simply "Bienes Raices" , not hard to see why, the "y" (and) was excluded to make it simpler and this is still the most widely used term. "Bienes Raices" literally means "Root Assets", one of the wonders of Spanish is that the way the phrase reads now, "Raices" became an adjective just by removing the "y" , while it was a NOUN in "Bienes y Raices"
2) Inmobiliario, depending on which country, may alternate w/Inmobiliaria but we should not view these as one is the "generic" and the other the "adjective" although I see where that comes from, if you look them up in the dictionary actually BOTH will be featured as NOUNS (which they are) and at the same time BOTH are ADJECTIVES (the letter O is usually for masc names if at the end of a word, while the letter A is normally fem when at the end of words) so it is the exact same term, one in masc, the other in fem, I myself would rather talk about "la industria inmobiliaria" (see the fem term, ending in A, being the adjective in this case) than simply "la inmobiliaria" which is also accepted but IMO not the best way to express it...."el mercado inmobiliario" is also often mentioned (the masc term, ending in O is also the adjective in this instance) and that term I also prefer to "el inmobiliario" which is also acceptable, and both la inmobiliaria and el inmobiliario roughly translate to our concept of real estate
So "bienes raices" (always masc plural) ; "bienes y raices" (also masc plural) ; "inmobiliario" and "inmobiliaria" will all do the job (I wouldn't use the plurals for inmobiliario(a) unless in specific instances, it doesn't translate well) But as far as keywords or generics that would attract the most hits, I'll defer this to some other poster, I haven't researched it and don't want to guess, I imagine BIENES RAICES would fetch you the most clicks
Can some other Hispanic DNF members (in Spain or Latin America) post their own opinion ? that would help and give us a better feel of what is actually used in the larger countries (Spain, Mexico, Argentina, etc) and even in the ads/news we see in Spanish right here in the US ...I hope my 2 cents helped !