I'm a small-time retail amateur and consider myself conservative with my portfolio (I stock-pick so that may be generous) so take this with a spoonful of salt. But to me, by buying in SPACs, or IPOs for that matter, one is trying to play VC's game. You're buying companies who have yet to prove their business model, who are likely far off from actual profitability - earnings before everything else (EBITDA) doesn't count - and whose valuations have a ton of future growth front-loaded. That may work if you have deep knowledge of a market, it's participants and how $X company fits in, but I suspect most people buying these young stocks don't have any particular knowledge of them. However with that in mind, the main issue to me is that one would be playing that game
after actual VCs had the opportunities to play during private rounds.
When cash-burning start-ups raise money on public markets at nose-bleed capitalizations and laughable (non-binding) projections, it begs the questions (1) why it's present investors are unwilling to fund it internally at more reasonable private valuations and (2) if the price they are offering you to pitch in at, on the public market, is optimized for current shareholders or new ones. I'd suspect (1) is because they're either ready to off-load their risk or unwilling to burn/risk more of their own cash and (2) it's obviously at the company's and it's present shareholders advantage. Sometimes it works out great, you'd have done brilliantly by investing in a now thriving company when it went public, but IPOs/SPACs are offering sloppy seconds on speculative companies.
My style is more akin to buying proven cash-cows at reasonable-ish valuations so I'm probably not the target demographic anyway, but I mostly wouldn't consider buying any newly traded company until people who bought the initial offering are in pain. I'll miss out on lots of boats this way, but I'm at peace with that.