70 is the equivalent of a Wealthy Rogue Trader. Nevertheless I want to get a feel or understanding of what it would mean for a Rogue Trader on the right side of the Imperium.
Mechanically, profit factor represents the probability that a PC (which is to say, a member of the Rogue Trader's coterie) can afford to buy something and maintain it indefinitely. The rules for this can be found on page 271 of the rules.
A profit factor of 70 is enough to 100% reliably afford a single lascarbine of standard make and all the ammo it'll ever need, a copy of Mefonte's Orthodoxy, a servoskull, a vox implant, or enough truncheons or backbacks for a whole company of mercenaries.
But talking in terms of what you can afford is misleading, because the real answer to "what does it mean to be a wealthy rogue trader" is wealth beyond the dreams of avarice. It represents being richer than most planet-ruling nobles, more liquid than planet-bound merchant princes. This wealth isn't just a giant pile of gold that you sit on, either - it's tied up in countless ventures, investments, and compacts that stretch across the imperium and generate even more wealth on an ongoing basis, until the coins pour in faster than you can count.
Granted, the coins also pour out again. Ventures, investments, and compacts don't pay for themselves, and the complexities of the sprawling universe mean that profits don't always pour in exactly when you need them - and as a result, a rogue trader can't always afford everything they want immediately, not without having to sacrifice business opportunities or sell off profit-generating important assets. This is why it's possible to fail acquisition rolls even with all that wealth, and why it's possible to overstretch profit factor.
Still, keep it in mind: Rogue traders with profit factor 70 aren't just rich, they're Richie Rich rich, and are assumed to live lives of unimaginable luxury unless stated otherwise.