Primary reasons that I trade FTSE Options are
1. When I first started trading options as retail:
... TOS would not open Accounts for UK based traders due to money laundering concerns
... IBKR only allow Accounts with restrictions for trading in Personal Pension Schemes
2. So built a system to "replicate" much of TOS functionallity for UK Options
3. FTSE has a relatively large Notional (£70-80k), European Style, Cash Settled, with reasonable liquidity, which I can trade in normal working hours, without any Currency Risk
Whilst most traders seem to apply the same strategy to lots of Tickers (that they know little about), I prefer to apply different strategies to one Ticker (that I know a little about) that reflect my best guess of market/vol conditions