I've been riding an e-bike myself for two years now and I can tell you it absolutely makes financial sense if you want to commute regularly. The electricity costs are really negligible - even with current prices you're probably paying like 3-5€ a month, which is ridiculous. The real advantage is that you arrive at work more relaxed, not completely drenched in sweat, and it gives you way more flexibility - for me that's made a difference in everyday stuff, no annoying traffic jams, no hunting for parking spots. 2800€ isn't cheap, but if it's a decent model it'll last you 5-10 years, and that easily pays for itself compared to driving a car, public transport yearly tickets or constantly wearing out regular bikes.