Please take my reply with a pinch of salt as I've never experienced buying any Bitcoin product on stock exchanges.

Anyway, in terms of safety, it's safe in a way because you're doing it on a highly regulated and compliant platform, but unsafe in a way because you don't actually own any real Bitcoin, only a kind of ETP. So, you aren't actually in control of your Bitcoin.

As to the price, I guess the crypto market and the stock market more or less mirror each other's Bitcoin price, but you'll probably spend more on fees and commissions when buying on the stock market.

By the way, are individuals or the retail market allowed to buy Bitcoin on LSE? Last I heard only professionals are allowed to do so.