Finance is a vast world and unfortunately too often reduced to pure speculation.
First you have basic lending and borrowing activities. The bank can afford to pay you interest (well not now that interest rates are at zero) only because your money is invested, usually in loans.
Then you have payments, cash management for companies.
Then you have more complex services offered to larger companies, raising capital (equity and debt) on the market, helping them manage their risk with derivatives (interest rate, currency, commodities (oil, metals, livestock, etc prices), inflation, etc) plus some advisory on corporate actions (mergers, IPOs, etc).
You have insurance, reinsurance.
And then you have asset management, which you can call speculation if you want, but which is essentially people managing investment portfolios on behalf of savers, pension funds, insurance premium for long term risks, etc. With a wide variety of approaches from very conservative money market funds which invest in highly safe and liquid assets, to trackers who try to replicate a benchmark by over performing it by a little, to investments in illiquid assets (property, non listed companies) or very aggressive/leveraged strategies (hedge funds). Fundamentally what they are doing is to ensure your money gets invested wisely (at least they try).
And of course all sorts of intermediaries: consultants, brokers, market data providers, research (sort of financial journalists), prime brokers (who provide financing when you leverage liquid financial assets), system providers, auditors, rating agencies, etc.
Now you could call everything speculation: when a bank lends you money, it bets on your financial soundness. When an investor takes the opposite side of a commodity (say oil) transaction, it bets on the price of oil. But that allowed you to get money to run a business or to offset an oil price risk that could have made you lose money if oil increased (say your are an airline company). There is no real dinstinction between risk taking / risk transfer and speculation. But in most instances it does have a social benefit.