Spanish and Catalan are easier than Russian because, from a English standpoint, very little changes. Besides a few quirks (like talking about body parts in spanish), they're very simple. No endings. You can tell the infinitive from conjugated verbs (and conjugate from there with ease). Pronunciation is easier in spanish since it's much more vowel sounds, and more syllables, the rolled r's are not a big deal in Spanish. Word order in Spanish is different, but straight forward, just takes practice, whereas with russian, I've found many sentences that I knew every word well, but had no idea what they were saying, based on word order and phrasing. English and Spanish phrasing are fairly similar, Spanish uses a more european style (But nowhere NEAR as much as Russian), but that's only a problem because English is one of the few language that doesnt use that style. Russian meaning changes based on the case relating words together, Spanish uses straight forward (need to be memorized still) preposition stacking.

Improving skill in Russian takes massive amounts of diligence and vigilance. Russian, being in a different alphabet than English, makes it very difficult to notice things you would normally notice immediately (word roots and relations, seeing a word multiple times), it also makes walls of Russian text look MUCH scarier than if they were in the Latin alphabet. I've heard people take 9 years to get well versed in Russian. I got to a poor "conversational"(single words responses, needing things to be repeated) level in about a year, and if I had been focused and hard working, I could be fluent right now, but I dont put in the work to read short stories and talk frequently with natives. Depends how much you want it. Look up Tim Doner. He learned 20 languages (learned well in about 5 years), it takes a lot of free time, and

Use of a language is... Determinable, yet not something that should be too important. Russia is awesome. Spanish is spoken in like half the world. Spanish is often used as a common language ground for business deals. Russian will give you good understanding of most of eastern europe. Hell, I can read basic Bulgarian. Depends on what you're using it for.